start using libformfactor

Polyhedron, associated classes, and some tests moved to external library.

Sample/Lattice/Lattice3D.cpp

@@ -89,7 +89,7 @@ std::vector<R3> Lattice3D::reciprocalLatticeVectorsWithinRadius(const R3 q, doub
                           index_Z + nearest_coords.z());
                 if (m_selection_rule && !m_selection_rule->coordinateSelected(coords))
                     continue;
-                R3 latticePoint = coords.x() * m_ra + coords.y() * m_rb + coords.y() * m_rc;
+                R3 latticePoint = coords.x() * m_ra + coords.y() * m_rb + coords.z() * m_rc;
                 if ((latticePoint - q).mag() <= dq)
                     ret.push_back(latticePoint);
             }