Adds 13 new operators.

* Adds bitwise left shift (<<), right shift (>>), OR (|), AND (&), and XOR (^) as well as their corresponding assignment operators (<<=, >>=, &=, |=, ^=) and bitwise NOT (~, one's compliment).
* Adds an exponent operator (**) and corresponding assignment operator (**=).
* Modified an existing test and inserted new tests to ensure the new operators function as intended and respect order of operations.
Touching up formatting, removing Math.Truncate calls, and allowing negative shift.
Merge pull request #5 from Syke94/master

Adds 13 new operators.