`area(CurvedPolygon)` methods work only with polynomial Bezier curves

[jcs15c]

Current methods implemented in compute_moments.hpp work only on nonrational/polynomial Bezier curve objects, in particular area(CurvedPolygon). Methods in evaluate_integral.hpp can be used to compute areas for CurvedPolygon objects when composed of rational Bezier curves (at the cost of an MFEM dependency), so we should consider using these methods in such cases to ensure that area(CurvedPolygon) can be used on the more general case.