Apple2C added. Doesn't work in the browser, though.

Fixed the buildtools target in the JSMESS Makefile. I need to go back and make the Makefile a bit more sane.

Caveat: Apple2C does not build properly since the 'buildtools' target for MESS does not build a buildtool that is only used to build the CPU core for the M68K. I looked and found a similar tool for a different CPU. Looks like I'll have to fix the MESS buildtools target, or have the JSMESS buildtools target compile a more "complete" MESS.
Two big changes:
* We now make systems, not systems+games. No more rebuilding the same emulator to use a different game!
* Templates are system-agnostic, so now we only have one simple template which all systems use. Hurray!
I forgot to add common.mak. Whoops!