Removed unused strings

Removed debugging strings from the source file.
Implemented '=' operator.

Implemented the '=' operator, which swaps VAR_A and VAR_B.
Implemented '+'

Implemented the '+' operator, which sets VAR_A equal to VAR_A plus
VAR_B.
Implemented '~'

Implemented the '~' operator, which assigns the value of NOT VAR_A
to VAR_A.
Implemented '^'

Implemented the '^' operator, which stores VAR_A XOR VAR_B into
VAR_A.
Implemented extra credit.

Implemented the 'y' and 'z' operators, which print VAR_A and VAR_B,
respectively, in the proper bit order.
Merge branch 'develop'