/**
    @addtogroup Notifications Notifications
    @ingroup Modules

    @ref orxonox::Notification "Notifications" are short messages, that can be sent from anywhere in Orxonox and then are displayed on the screen to inform the user about some occurence he has to know about. Such an occurence could be, that he just shot and killed his Archnemesis Overlord3, that he just got a new Pickup or that he received a Quest and needs to have a look at the Quest-Menu.

    @section NotificationsUsage Usage
    Let's very briefly talk about what you have to do to either send @ref orxonox::Notification "Notifications" from some part of Orxonox or display Notifications on your screen.

    @subsection NotifictionsSending Sending notifications
    Sending a new @ref orxonox::Notification "Notification" from (almost) anywhere in Orxonox is fairly easy.
    You first have to decide on a message, it shouldn't be too long but be long enough to get your point accross.
    Then you have to decide on a sender. The sender is a string by which the different @ref orxonox::NotificationQueue "NotificationQueues" (the entities that display the @ref orxonox::Notification "Notifications") can decide whether they should display the @ref orxonox::Notification "Notification" or not. So the sender is some string that identifies a group of @ref orxonox::Notification "Notifications" that have something in common or some entity that is sending them. For example: All @ref orxonox::Notification "Notifications" sent by any part of the Questsystem have "questsystem" as sender and thus we could create a @ref orxonox::NotificationQueue "NotificationQueue" that only displays @ref orxonox::Notification "Notifications" from the Questsystem, but more to that later.
    And lastly you have to decide to whom you want to send this @ref orxonox::Notification "Notification". You have to get the clientId of the intended recipient (e.g. trough a @ref orxonox::PlayerInfo "PlayerInfo") or you only send the @ref orxonox::Notification "Notification" locally, either by setting the clientId to Host::getPlayerID() or by setting the variable 'isLocal' to true, and setting clientId to what ever you want, since it will be ignored.
    Once you have decided all that you can send the Notification by calling:
    @code
    NotificationManager::sendNotification(message, clientId, sender, isLocal); // isLocal = false can be ommitted since that is the default value.
    @endcode

    @subsection NotificationsDisplay Displaying notifications
    Displaying @ref orxonox::Notification "Notifications" is even easier, all you need to do is to load the NotificationLayer in the level, where you want @ref orxonox::Notification "Notifications" displayed. You can either do this manually by executing the following command in the console:
    @code
    showGUI NotificationLayer false true
    @endcode
    Or automatically, by adding a @ref orxonox::Script "Script" to the levelfile that does it for you:
    @code
    <Script code="showGUI NotificationLayer false true" needsGraphics="true" />
    @endcode

    If you want to change the way the @ref orxonox::Notification "Notifications" are displayed, you can enter the (at this point rather rudimentary) edit mode and add new @ref orxonox::NotificationQueue "NotificationQueues" or change position and properties of the existing ones, by executing the following command in the console:
    @code
    enterEditMode
    @endcode

    @section NotificationsTechincalDetails Technical details
    The Notifications module has three major parts that interact with each other. First there is the @ref orxonox::NotificationQueue "NotificationQueue", this is the entity that (logically, not effectively) displays @ref orxonox::Notification "Notifications" according to some rules, then there is the NotificationLayer, which is the GUI which (actually) displays @ref orxonox::Notification "Notifications" by visualizing the @ref orxonox::NotificationQueue "NotificationQueues" and as a result also the @ref orxonox::Notification "Notifications", that are displayed by the respective @ref orxonox::NotificationQueue "NotificationQueues" and lastly there is the @ref orxonox::NotificationManager "NotificationManager", which connects these two.

    @subsection NotificationQueue NotificationQueue
    The @ref orxonox::NotificationQueue "NotificationQueue" is the entity, that (as said earlier) logically displays @ref orxonox::Notification "Notifications". Furthermore a @ref orxonox::NotificationQueue "NotificationQueue" displays only a subset of all the @ref orxonox::Notification "Notifications". The parameters that reduce the range of displayed @ref orxonox::Notification "Notifications" are:
    - @b senders The senders, the set of targets of a @ref orxonox::NotificationQueue "NotificationQueue" is the set of senders a @ref orxonox::NotificationQueue "NotificationQueue" displays  @ref orxonox::Notification "Notifications" from. E.g. If one would set the senders to "questsystem" then only  @ref orxonox::Notification "Notifications" from the Questsystem would be displayed in that particular queue. If you set senders to "all" then all Notifications will be displayed. Different senders can be concatinated with commas.
    - @b size The size specifies how many @ref orxonox::Notification "Notifications" are displayed at the most, if there are more @ref orxonox::Notification "Notifications" that could be displayed, then only the most recent are displayed.
    - @b displayTime The display time specifies how long a @ref orxonox::Notification "Notification" is displayed at the most.

    @subsection NotificationLayer NotificationLayer
    The NotificationLayer is a GUI sheet, that displays all the @ref orxonox::NotificationQueue "NotificationQueues" and their @ref orxonox::Notification "Notifications". In its normal mode of operation it is transparent to input, meaning that it only functions as a means of displaying, however if switched to edit mode the NotificationLayer no longer is transparent to input and allows for the adding, removal and modification of @ref orxonox::NotificationQueue "NotificationQueues". For every @ref orxonox::NotificationQueue "NotificationQueue" there is the equivalent representation in the NotificationLayer. So @ref orxonox::NotificationQueue "NotificationQueues" are not each represented by a GUI sheet, but thely all belong to one and the same GUI sheet, the NotificationLayer.

    @subsection NotificationManager NotificationManager
    The @ref orxonox::NotificationManager "NotificationManager" is (hence the name) the managing entity in this setting. It is responsible for the registering and unregistering of @ref orxonox::NotificationListener "NotificationListeners" (which the @ref orxonox::NotificationQueue "NotificationQueue" is) and also informs them about changes related to @ref orxonox::Notification "Notifications". It is also responsible for the creation and destruction of @ref orxonox::NotificationQueue "NotificationQueues" through the NotificationLayer and is also the point of approach for the NotificationLayer to get information it needs to display the queues. Finally the @ref orxonox::NotificationManager "NotificationManager" is responsible for sending (and in the process creating) @ref orxonox::Notification "Notifications" and is a means for the @ref orxonox::NotificationQueue "NotificationQueues" to get the information they need about @ref orxonox::Notification "Notifications".

    @subsection Notification Notification
    The @ref orxonox::Notification "Notification" class is more or less a data structure that groups the notification message and the sender, and possibly other future parameters, together to form a comprehensive structure that we call Notification.

    Additionally there is another important class of objects belonging to the Notifications module. The @ref orxonox::NotificationDispatcher "NotificationDispatchers".

    @subsection NotificationDispatcher NotificationDispatcher
    @ref orxonox::NotificationDispatcher "NotificationDispatchers" are entities that are instantiated in a level file (through XML) and that dispatch (or send) a specific @ref orxonox::Notification "Notification" upon having received a triggering event.

    @defgroup NotificationDispatchers Dispatchers
    @ingroup Notifications

    @ref orxonox::NotificationDispatcher "NotificationDispatchers" are entities that are instantiated in a level file (through XML) and that dispatch (or send) a specific @ref orxonox::Notification "Notification" upon having received a triggering event.

    At this point there are two @ref orxonox::NotificationDispatcher "NotificationDispatchers", the @ref orxonox::SimpleNotification "SimpleNotification", which just displays a specified message, and the @ref orxonox::CommandNotification "CommandNotification" which displays a message with a binding for a specified command in it.
*/