Updated basic math functions (add, subtract, multiply, divideBy) to be non-static. Updated code which used those functions.
Added eval method for Monomials and Polynomials (both types).
add(Monomial) and subtract(Monomial) for Polynomials now remove terms generated with a 0 coefficient from the Polynomial.
Fixed sort so sorts Monomials from high to low order.
Added print methods for Monomials and Polynomials (both types).