getSimulationPatch API, modified ArnoldPatch and a intensity changer for GUI

Now it's possible to get the ArnoldPatch instance from rig, so the caller can
get access to virsualization-related infos via ArnoldPatch function. Arnold-
Patch uses a separate loop to render which makes abort and restart with new
light parameters possible. Also, most of Arnold API calls were pulled out from
ArnoldPatch. They are handled by ArnoldInterface class now. A simple slider
was added to GUI. Users can change intensity of the light and re-render the
scene.
Changed AiRenderAbort to AiRenderInterrupt