Cycles: Add "Max Bounce" control for lamps

With this setting, we can limit the influence of a lamp to a certain amount of bounces.
0 = Only direct light contribution
1 = 1 light bounce
...

Differential revision: https://developer.blender.org/D860

You can find an example render in the release logs: http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.73/Cycles

intern/cycles/blender/addon/properties.py

@@ -653,6 +653,12 @@ class CyclesLampSettings(bpy.types.PropertyGroup):
                 min=1, max=10000,
                 default=1,
                 )
+        cls.max_bounces = IntProperty(
+                name="Max Bounces",
+                description="Maximum number of bounces the light will contribute to the render",
+                min=0, max=1024,
+                default=1024,
+                )
         cls.use_multiple_importance_sampling = BoolProperty(
                 name="Multiple Importance Sample",
                 description="Use multiple importance sampling for the lamp, "