Fixed gcc warnings for unused var and unitialiazed vars.

NOTE: I had to fix NMesh.c, Mesh_fromNMesh(), that is a real bad
function... it was returning a Py object as a Mesh (on error).
This is still not really solved (NULL return is not handled).

source/blender/python/api2_2x/Mathutils.c

@@ -486,8 +486,9 @@ PyObject *M_Mathutils_AngleBetweenVecs(PyObject * self, PyObject * args)
 	}
 	dot /= (sqrt(test_v1) * sqrt(test_v2));
 
-	if (dot < -1.0f || dot > 1.0f) 
+	if (dot < -1.0f || dot > 1.0f) {
 		CLAMP(dot,-1.0f,1.0f);
+	}
 	angleRads = (double)acos(dot);
 
 	return PyFloat_FromDouble(angleRads * (180/ Py_PI));