Changeset 8633 for code/branches/unity_build/src/BuildUnitsConfigGCC.cmake

Optimised build units for MSVC too by splitting the config file in two.
Note that I had to guess the values for 8 threads, I can not (yet) test that.
Also note that the MSVC config applies to having MSVC configured to make N targets at once (leading up to possibly N*N processes). Seems stupid, is stupid, but is still the fastest when compiling Orxonox.