Split GLMesh away from IGLComponent and renamed to Mesh

This is part 1 where GLMesh becomes a Mesh resource.

Part 2 will change OpenGLSystem to accept the new renderable component
which contains a Mesh resource.

Added resource src files to CMakeLists and added a filter to ensure the cef_* files don't get included in the project directly.
Moved the other GLxxx resources into resources

These items were previously components, but are now specialized forms of the Mesh resource.
Renamed IGLComponent to Renderable and moved into components folder

Also fixed factory functions in OpenGLSystem to reflect the new resource/renderable split.

Fixed some includes in GLSprite.h and Mesh.cpp