(MESS) horizon.xml: Added floppies. [Andrew Lynch]

git-svn-id: svn://dspnet.fr/mame/trunk@23315 749742ba-7341-0410-aadc-df50b521781e
(MESS) abc80x, abc1600: Added Luxor ABC keyboard port slot interface. [Curt Coder]

git-svn-id: svn://dspnet.fr/mame/trunk@23316 749742ba-7341-0410-aadc-df50b521781e
(MESS) softbox: Added CP/M hard disk installation instructions. [Mike Naberezny]

git-svn-id: svn://dspnet.fr/mame/trunk@23317 749742ba-7341-0410-aadc-df50b521781e