Changed 32 bit register names to 64 bit register names (example: eax -> rax)
changed ebp to rsp (because that's the way x86-64 works). more changes might be needed, but this seems good for now.
renamed 32 bit registers to 64 bit registers.
updated print function to work properly for 64 bits.
shedding 32 bit baggage to just support 64 bit. added all the 64 bit registers, too.