Disable extra pivot nodes added by Assimp.
Improved material support.
Materials were not being assigned to the geometry.
Missed adding helper.
We skip adding nodes associated to meshes.
Added skeletion for MeshHelper static class.
Added MeshHelper.CalculateTangentFrames().
Added MeshHelper.FindSkeleton().
Added MeshHelper.SwapWindingOrder().
We now try to build a full path for assembly references.
We now dump the inner exception when content fails to build.
Merge branch 'fbxfix' into stable_BtA