[CPU] - sync Memory <-> CPU and add step() after rom-validation

[Waterfountain10]

What to do:

• CPU::attach_memory in cpu so that it can reference pointe : memory_ -> some Memory class with all the juice

Criteria:

• must be able to write a step() in cpu, that goes into memory -> read-byte(pc++) and return the opcode!
• add some debugging for the step() as well as the attach_memory, so we can read easily