Desktop OpenGL and OpenGL ES 2 support can be switched using CMake
TARGET_GLES option. All functionality not supported in ES is marked in
documentation.
If targetting OpenGL ES, GLES2/gl2.h is included instead of GLEW.
Mesh class now uses VAOs only in desktop OpenGL, in ES the buffers are
bound on each draw call.
* All attribute pointers and buffer binding is now stored in each
mesh own vertex array object, thus each mesh drawing now needs
only three OpenGL calls.
* Removed default VAO from Scene, which fixes unit test crashes.
* Renamed Type enum to Target to be consistent with OpenGL naming
* Strongly typed enums
* Ability to specify different type when binding/setting data
* Added missing buffer targets