This is for Vulkan preparation where all of this needs to run in a user-specified context so that this code can be moved out of the GL folder without depending on OpenGL's global state model.
The binding point needs to be part of the ShaderUniforms class because Vulkan will need this value to generate the declaration in the shader source.
There's still one issue here: Since OpenGL has no local render state, the buffer must be bound every time it is used. Once the code is better abstracted this should be moved to a higher level class that knows all associated data and how to set it up.
Added gl_renderbuffers CVAR that disables render buffers
Added patch shader support to FShaderProgram
Added OpenGL 2 fallback support to render buffers
