TMeshCache<x,y,z>::request_mesh_indicies now has an out-param for primitive type.
Actually implement class virtuals on OpenGL::DeferredRenderer
Finish OpenGL::DeferredRenderer::process_renderable, a method that iterates through the entire scene and draws it to the G-buffer

Also split off material configuration to set_material_parameter.
Fix improper definition of function & coding standards
More function stub impls for OpenGL::DeferredRenderer
Properly set the input texture units on the gbuffer fragment shader