python: adapt to deprecated Math::angle() for quaternions.

It's renamed to half_angle() here as well. No API deprecation, sorry.

src/python/magnum/math.cpp

@@ -269,8 +269,10 @@ template<class T> void quaternion(py::module_& m, py::class_<T>& c) {
     m
         .def("dot", static_cast<typename T::Type(*)(const T&, const T&)>(&Math::dot),
             "Dot product between two quaternions")
-        .def("angle", [](const T& a, const T& b) {
-            return Radd(Math::angle(a, b));
+        .def("half_angle", [](const T& a, const T& b) {
+            /** @todo switch back to angle() once it's reintroduced with the
+                correct output again */
+            return Radd(Math::halfAngle(a, b));
         }, "Angle between normalized quaternions", py::arg("normalized_a"), py::arg("normalized_b"))
         .def("lerp", static_cast<T(*)(const T&, const T&, typename T::Type)>(&Math::lerp),
             "Linear interpolation of two quaternions", py::arg("normalized_a"), py::arg("normalized_b"), py::arg("t"))

src/python/magnum/test/test_math.py

@@ -1144,8 +1144,8 @@ class Quaternion_(unittest.TestCase):
         self.assertAlmostEqual(float(Deg(a.angle())), float(Deg(45.0)), 4)
 
     def test_functions(self):
-        a = math.angle(Quaterniond.rotation(Deg(45.0), Vector3d.x_axis()),
-                       Quaterniond.rotation(Deg(75.0), Vector3d.x_axis()))
+        a = math.half_angle(Quaterniond.rotation(Deg(45.0), Vector3d.x_axis()),
+                            Quaterniond.rotation(Deg(75.0), Vector3d.x_axis()))
         self.assertEqual(Deg(a), Deg(15.0))
 
     def test_properties(self):