Updated Polynomial Tests

Now has explicit sparse and dense instances of tests
Still failing quotmod test for dense polynomial
Dense quotmod fixed

dense quotmod now functions as expected
separated the tests into dense and sparse variants
Updated sparse quotmod logic to follow dense now using Arrays

Sparse quotmod is slower than dense quotmod probably due to
requirements for coeff array formation and then long division followed
by conversion to Terms -> Map again. Whereas in dense, coeffs already
exist as LE style arrays ready to go.
Perhaps could do some updates on Array methods to stop scala wrapping
unwrapping
Dense & Sparse Polynomials Working & Benchmarked

Fixed quotmod in dense polynomials
Added toDense, toSparse capability in Polynomial trait
Added sparse and dense benchmarking
Added sparse and dense tests to check equivalence

Speed now quite fast for dense Polynomials using Doubles with
specialization. I estimate for most functions we see par to 25% worse
performance vs. commons math.