[GL] Remove twice implemented functionality.

GeoLib/AnalyticalGeometry.cpp

@@ -330,14 +330,6 @@ double calcTriangleArea(MathLib::Point3d const& a,
 	return 0.5 * w.getLength();
 }
 
-double calcTetrahedronVolume(const double* x1, const double* x2, const double* x3, const double* x4)
-{
-	const MathLib::Vector3 ab(x1, x2);
-	const MathLib::Vector3 ac(x1, x3);
-	const MathLib::Vector3 ad(x1, x4);
-	return std::abs(GeoLib::scalarTriple(ac, ad, ab)) / 6.0;
-}
-
 double calcTetrahedronVolume(MathLib::Point3d const& x1,
 	MathLib::Point3d const& x2,
 	MathLib::Point3d const& x3,

GeoLib/AnalyticalGeometry.h

@@ -139,7 +139,6 @@ double calcTriangleArea(MathLib::Point3d const& a, MathLib::Point3d const& b,
  * Calculates the volume of a tetrahedron.
  * The formula is V=1/6*|a(b x c)| with a=x1->x2, b=x1->x3 and c=x1->x4.
  */
-double calcTetrahedronVolume(const double* x1, const double* x2, const double* x3, const double* x4);
 double calcTetrahedronVolume(MathLib::Point3d const& x1,
 	MathLib::Point3d const& x2,
 	MathLib::Point3d const& x3,