Ok, try 2.

snesnew and snespnew are now gone, and the new code is used directly in snes and snespal. This means we have also removed the fake clones needed to run games with addon chips:
- no more snessfx and snespfx to run SuperFX games,
- no more snesdsp,snespdsp, snesst10 and snesst11 to run DSPx games,
- no more snesst to run ST carts
everything just loads in snes and snespal

a couple of details about the DSPx games: these games require the dump of the NEC/SETA DSP CPU to run...
from softlist, this data is contained in the romset itself (the CPU was on the cart) so everything just works.
from fullpath, this data has to come from somewhere else, and the solution (to avoid adding yet another fake clone like I did yesterday) is to use device roms. so you just need to build latest svn and rebuild with cmpro from the old clone bios romsets to end up with all the roms you need to run DSP games.

In addition, DSP dumps used by higan which contains the CPU data appended at the end of the game are supported as well. Hence, you can optionally append the DSP data to the .sfc file (both using our 0x2800 DSP dumps or byuu's stripped down 0x2000 versions) and that data will be used, which allows you to test what will happen using e.g. a DSP1B dump into a DSP1/1A game and so on...

everything wonderful, so far? well, the new code has a drawback: a performance hit which is usually ~5% (but some games are actually faster than they were, depending on how often they do access the cart) and which goes up to ~20% for DSP games
the additional overhead is generically due to the usage of slot devices, but there seems to be something more going on on DSP games and I will try to isolate it ASAP...