BlenderBMeshConverter assumes that the BMesh has UVs, but that is not
always the case. Handle the non-UV case by only adding a T face when
UVs are present.
- Added BlenderBMesh.cpp/h which contains a class to convert a BMesh to an old style tri/quad mesh
- Added BlenderTessellator.cpp/h which contains a class to tessellate the poly loops contained within a BMesh