cleaned up. nw.
Removed unused field, thanks Al (nw)
fixed a couple of regressions. nw.
hangplt have different memory map (nw)
removed CassetteOptions that is already default (nw)
image.c: Added support for loading a default battery, instead of a fixed fill value, when no
battery is found. This allows for loading factory formatted sram/nvram from softlist. [Fabio Priuli]

(MESS) nes.c: Fixed Silva Saga, which relies on SRAM not being 0x00 filled from factory,
with many thanks to naruko for investigating the problem. [Fabio Priuli]
hexion.c: remove long obsolete comment (nw)
softlists: added a bunch of new dumps, courtesy of Ola Andersson, SMS Power, 
TeamEurope, Matt Taylor and taizou. nw.
Cleanup of image device interfaces (nw)
(MESS) nes.xml: added correct nvram to dezaemon, thanks to naruko's 
research [Fabio Priuli]
webengine: fixed a memory leak, after Firewave's suggestion. nw.
fixed sfrush sound regression (nw)
centiped.c: fix generic_paletteram regression (nw)
cassette config moved inline (nw)
williams.c: fix generic_paletteram regression (nw)
(mess) rmnimbus: extract keyboard and use z80dart and wd_fdc (nw)
small optimization to device_execute_interface::local_time() (nw)
hunter2: removed some outdated notes, and fix RAM size detection.  It now gives a more realistic amount of free space after a format of the ramdisk.
williams.c: move blaster-specific stuff into subclass (nw)
williams.c: move williams2-specific stuff into subclass (nw)