polys: Fixed doctest failure in sqfreetools.py
polys: Added mulpow(A, B, exp) to MonomialOps
polys: Added remaining is_* methods to PolyElement
polys: Added degree() and friends to PolyElement
polys: Added exquo() to PolyElement and added division related tests
polys: Cleaned up division operators in PolyElement and enabled a test
polys: Added l1_norm() to PolyElement and simplified code
polys: Better order of methods in PolyElement