Changing 'bob' references to 'hamming' in hamming/GETTING_STARTED.md

Not sure if hamming/GETTING_STARTED.md was intended to be more of a template, or to specifically call out the hamming exercise.  Assuming the latter I've updated the references to 'bob' with 'hamming' and addressed the other anomalies.
Oh, I see what happened -- global search/replace for `hey`.