This adds RzIL lifting for all legal 6502 ops, except the special bcd
modes of adc and sbc for now. The lifting of every one of these ops is
covered by an asm test, making sure all IL is valid. Some manual
execution tests are available too, including one that runs a simple
real-world xor-"decryption" loop.
The lifting has not been tested against traces yet, so minor mistakes in
the semantics are currently expected.