smooth PNode

[patrick]

implement a PNode (Parent Node) that doesn't follow its parent at once, but glides smoothly after it.

• concrete use
  • camera that smoothly follows the player
  • a wingman that will follow you with a delay and smooth

• requirements
  • set the delay of an action
  • set the smooth factor: how fast a child shall follow its parent

[bensch]

Implemented the stuff inside of PNode this could also be implemented as a plugin, if the need (speed) arises

but, i think, on the way many other efficiency-patches were done, so ther is no need, to double the effort