Move the domain enums to dvd_types.h from vm.h
Change the type of old_domain and new_domain

I am guessing that old_domain and new_domain are really storage for
dvdnav domains and not dvdread domains.
Add in comments to the domain enum
Change the enum name to match the style
Change each enum name to match the style
Change all of the domain_t declarations to DVDDomain_t
Switch over all the old domain enum names to the new names
Remove the old commented out domain enums