Drop the usage of ARB_compute_variable_group_size and specialize compute
shaders instead. This permits compute to run on AMD and Intel
proprietary drivers.
Replaces header inclusions with forward declarations where applicable
and also removes unused headers within the cpp file. This reduces a few
more dependencies on core/memory.h
Removes a few unnecessary dependencies on core-related machinery, such
as the core.h and memory.h, which reduces the amount of rebuilding
necessary if those files change.
This also uncovered some indirect dependencies within other source
files. This also fixes those.
When I originally added the compute assert I used the wrong
documentation. This addresses that.
The dispatch register was tested with homebrew against hardware and is
triggered by some games (e.g. Super Mario Odyssey). What exactly is
missing to get a valid program bound by this engine requires more
investigation.
