Added proper evaluation. Removed Execute() as unnecessary. If parent
calls for a value with element() or toString() method, evaluates within
that method.
Moved bracket checking to Util class
Added new inherited execute() but unused
Multiple Changes, rework of code.
Ordering added.
Flattens child Functions correctly.
Adds variables and represents correctly.
Multiple Changes, rework of code.
Ordering added.
Flattens child Functions correctly.
Multiplies variables and represents correctly.
Multiplies by zero correctly.
Variables now only tokenized to be one character long. (XYZ is 3 vars)
Variables and coefficients entered as a MultipleFunctionElement
Now implements Comparable (by String output)
Reworked execute() to fit new parent specifications
Added new test cases. Failing cases marked