Make cpu pc attribute private
Re-implement jr op making it take immediate as argument
Implement JR,NZ r8 opcode
Implement JR Z,r8 opcode
Implement JR NC,r8 opcode
Implement JR C,r8 opcode
Underscore unused arguments
Remove unused dependency
Modularize opcodes

Try to reuse loads and such instead of writing a function to correspond to each op
Remove all piston stuff

I'll worry abour rendering later
Decode ops using macro for disarm
Implement a bunch of loads
Implement logical ops