added dual tvl1 optical flow implementation
added dual tvl1 optical flow gpu implementation
added enqueueHostCallback method to gpu::Stream
added gpu compare with scalar
added mask support to gpu norm and sum
added gpu::normalize function
added gpu::HoughLinesP function
added gpu BM optical flow implementation
added Warp::reduce function
added gpu optical flow sample
added perf4au app
refactored OpticalFlowDual_TVL1:

* added DenseOpticalFlow interface
* moved OpticalFlowDual_TVL1 to src folder
Merge pull request #485 from jet47:gpu-new-functionality