Native bindings to the NV_uniform_buffer_unified_memory extension.

This extension provides a mechanism to specify uniform buffers using GPU addresses.

Binding uniform buffers is one of the most frequent and expensive operations in many GL applications, due to the cost of chasing pointers and binding objects described in the overview of NV_shader_buffer_load. The intent of this extension is to enable a way for the application to specify uniform buffer state that alleviates the overhead of object binds and driver memory management.