The move constructor/assignment of `Polynomial` is incorrect

[Ovascos]

The move constructor of Polynomial is actually a copy constructor:

libpoly/src/polyxx/polynomial.cpp

Lines 61 to 62 in fc54e31

	Polynomial::Polynomial(Polynomial&& p)
	: mPoly(lp_polynomial_new_copy(p.get_internal()), polynomial_deleter) {}