some experiments
async
fixed fp problem
moved kernelToStr to ocl.hpp
workaround
simplified cv::boxFilter OpenCL impl
OCL module 2 trash
cached commonly used device properties
redundant clFinish in upload since clEnqueueWriteBuffer above is already blocked
imgproc/intersection: fix loop index
Merge pull request #2246 from alalek:intersection_loop_bug
Merge pull request #2245 from ilya-lavrenov:redundant_sync
Merge pull request #2244 from ilya-lavrenov:tapi_device_cache
Merge pull request #2236 from ilya-lavrenov:tapi_boxfilter
Merge pull request #2243 from ilya-lavrenov:ocl2trash
Merge pull request #2228 from ilya-lavrenov:tapi_experiments