Optimize the clients FPS

[Anderen2]

The clients FPS is too low to be playable at some times. It should be over 60FPS at my HP Probook 4330s (Intel Sandy Celeron, Intel HD 3000)

[Anderen2]

After terrain optimalizations in commit: 50226a0 the game is now running at 80-90 FPS with an empty scene (Only map with few decorations)

Though after adding 10 planes into the scene it slows down to ~60. If they are moved (Without particles and dbg_aabb but with FOW) they go down to ~40 (Which is too low)

Im setting the limit for fixing this bug at min. 15 moving entitys and 5 decorators in view with fow. This should run over 60FPS