Fixing some windows build issues.
Fixed tracing bug and improved tracing in meshes with degenerate parameter faces.
OpenMesh doesn't support non-manifold meshes. Non-manifold meshes,
may arise when collapsing faces parametrized to zero area. For now
we're simply ignoring such faces. Since subsequent steps in the
processing pipeline rely on the total absence of such faces, this
causes crashes or holes in some cases.