Dependencies on vkparse.hinc were spreading through the code which I
didn't want as that removes a lot of the automation from the automake
files. This keeps all parser code internal to vkparse.c's scope, and any
accesses required for enum and struct (not yet) definitions can be
fetched by name.
Shaders can be built as spv files and installed into
$libdir/quakeforge/shaders or as spvc files and compiled into the
engine. Loading supports $builtin/name to access builtin shaders,
$shader/path to access external standard shaders and quake filesystem
access for all other paths.
