While namespaces act for hierarchy, modules are something like "tags" -
usable when you want to check related classes of e.g. CubeMapTexture.
Not sure how to name module for Math and Physics namespaces and
Contexts/Trade, though.
Fixed a few typos in extension names, fixed BPTC texture compression
typos. Removed redundant EXT_framebuffer_object from functions as the
Framebuffer class itself has it.
The compiler will produce error anyway, because the body of the function
is not implemented, only in explicit template specializations. Deleting
the function would make sense if there was another function with the
same name taking different argument, which is not this case anyway.
The requirements are cross-referenced to dedicated page, similarly to
TODO and bug lists.
Also updated / improved documentation for some texture / image formats.