Add bitwise ops and base conversion (DEC/OCT/HEX) in TI mode
These operations implicitly truncate their parameters, and result to integers:
Base 2 was left out of the base conversion code intentionally as it would require making the UI at least one third wider.
Attempts to change base with negative values will simply display "error." Note that with larger numbers, the result may be inaccurate due to rounding.
I've also bound the Return key to the equal() action.