remove prototype pathops code

experimental/Intersection/QuadraticParameterization.h

-#include "DataTypes.h"
-
-class QuadImplicitForm {
-public:
-    QuadImplicitForm(const Quadratic& q);
-    bool implicit_match(const QuadImplicitForm& two) const;
-
-    double x2() const { return p[xx_coeff]; }
-    double xy() const { return p[xy_coeff]; }
-    double y2() const { return p[yy_coeff]; }
-    double x() const { return p[x_coeff]; }
-    double y() const { return p[y_coeff]; }
-    double c() const { return p[c_coeff]; }
-
-private:
-    enum Coeffs {
-        xx_coeff,
-        xy_coeff,
-        yy_coeff,
-        x_coeff,
-        y_coeff,
-        c_coeff,
-        coeff_count
-    };
-
-    double p[coeff_count];
-};