Started MBC3/Debugging opcodes

Started MBC3 code. Still need to finish rtc and other clock related stuff for mbc. added new argument to print opcodes to stdout(-rp instead of -r).started attempting to debug cpu now that pokemon gold runs(barely). relative jumps still aren't working correctly so I might have to redo some stuff related to when the program counter updates. Also removed comment from halt opcode so it behaves like nop(shouldn't be a huge problem since halt would execute the next opcode). I should probably added some halt variable to let emulate() keep running and checking for keypresses to cause interrupts.