Use Y axis as up direction in physics code; this breaks simulation!
Merge branch 'master' of github.com:freescale-cup-simulator/simulator into same-up

Conflicts:
	src/global_renderer.cc
Merge branch 'master' of github.com:freescale-cup-simulator/simulator into same-up
Merge branch 'master' of github.com:freescale-cup-simulator/simulator into same-up
Merge branch 'master' of github.com:freescale-cup-simulator/simulator into same-up
Same up direction everywhere; Use car trimesh in physics simulation.

Dropped Assimp, trimesh data is now imported from Ogre.
Cleaned up resources.
Added wheel data to DataSet
Display wheels; also fixed bounding boxes not being updated
Adjust wheel slip direction to allow realistic steering