Completed PC testing successfully (possibly more methods to add to PC class).
Fleshed out RegisterFile16 code.
Added test for RegisterFile16 (array of 16 general purpose registers).
Discovered (rather important) typo in RegisterFile16 read() method when testing (less than sign present where greater than sign ought to have been). Error now corrected.
RegisterFile16 testing complete so far; all successful. If more methods are added, these will be tested at that time.
Continuing to flesh out ControlUnitImpl code; structure may change depending on how current line of design goes.
Drafted out more code; all subject to change at this point.
Put new ideas in comments.