Stop the flipping insanity [Alex Jackson]

Tilemap flipping is now calculated relative to the center of the visible area
rather than to the total screen size, and the generic flip screen functions
no longer reconfigure the actual screen.
These changes ensure that in most cases flipping should Just Work for drivers
that use MCFG_RAW_PARAMs, games that have a programmable CRTC, and games that
have raster effects, and should fix many longstanding flip/cocktail-related
regressions.

(nw)
Unfortunately, it also means that all the thankless work that Osso and hap
have been doing over the last few months fixing flipscreen regressions will
have to be reverted now. I've also undoubtedly caused new regressions in
drivers that handle flipscreen in unusual ways. But now we can share video
device implementations between drivers that have been updated to RAW_PARAMs
and drivers that haven't without kludges all over the place.
And now I can hook up the programmable CRTC in toaplan1.c without abandoning
all hope of flipscreen ever working again in that driver.

(also nw)
I also added savestate registration for the generic soundlatches, which seemed
like a good idea. Any particular reason why these weren't being saved?