game engine: implement hitMaterial for collision and ray sensors

Reviewed By: moguri, kupoman

Differential Revision: https://developer.blender.org/D167

doc/python_api/rst/bge_types/bge.types.KX_RaySensor.rst

@@ -51,6 +51,12 @@ base class --- :class:`SCA_ISensor`
 
       :type: list [x, y, z]
 
+   .. attribute:: hitMaterial
+
+      The material of the object in the face hit by the ray. (read-only).
+
+      :type: string
+
    .. attribute:: rayDirection
 
       The direction from the ray (in worldcoordinates). (read-only).

doc/python_api/rst/bge_types/bge.types.KX_TouchSensor.rst

@@ -39,3 +39,9 @@ base class --- :class:`SCA_ISensor`
 
       :type: :class:`CListValue` of :class:`KX_GameObject`
 
+   .. attribute:: hitMaterial
+
+      The material of the object in the face hit by the ray. (read-only).
+
+      :type: string
+