added readlatch (dummy read is documented by Yamaha)

git-svn-id: svn://dspnet.fr/mame/trunk@23359 749742ba-7341-0410-aadc-df50b521781e
renamed for consistency (nw)

git-svn-id: svn://dspnet.fr/mame/trunk@23360 749742ba-7341-0410-aadc-df50b521781e
guttangt - added rom banking so that the music plays (because they had to rewrite the sound / music for galaxian hardware and there wasn't enough rom space they bank it at 0x2000)



git-svn-id: svn://dspnet.fr/mame/trunk@23361 749742ba-7341-0410-aadc-df50b521781e