Added assimp submodule and penciled in scene loader for it.
updated assimp submodule
ASSIMP loader is building proper hierarchy (at least for collada).  Still some bad mem access with big meshes in glDrawElements.
WIP trying to track down memory problem with VAO/VBO.  Very close.
Fixed VAO/VBO crash in glDrawElements.  Was using uint16_t as return type for number of bytes in vert attribute storage, but that could easily overrun, even when using uint16_t indices.  Still need to clean up some of the troubleshooting code and related improvements.
updated assimp with project link warning fix
Cleanup of assimp mesh building static/dynamic validity checking.
Added basics of texture meta data loading from assimp.  Penciled in progFactory.
Working ASSIMP loader (at least for DAE), added texture::Semantic, and did some other cleanup.
Merge branch 'assimp'
Updated readme.