Cycles: * Disable Lamp MIS on sm_20. Still enabled for CPU and sm_21 and above. 
Cycles:
* Disable Lamp MIS on sm_20. Still enabled for CPU and sm_21 and above. 

pyrochlore/cycles,tangent-opensource/coreBlackbird,pyrochlore/cycles,tangent-opensource/coreBlackbird,tangent-opensource/coreBlackbird,pyrochlore/cycles