add some gitignores for non-vpath builds
replace cpu with 6502 emulator
remove v6502.cpp (shouldn't have been added in the first place)
fix gitignore for executable (for non VPATH builds)
turn off register tracing of 6502 emulator
fix display of power light
add compiler option (#define) for using 6502 emulator or simulator
update for autoconf 2.69
bring back audio; use 48KHz
reduce screen types to the most interesting 3