added OpenCL-accelerated(?) FAST; for now the tests fail :(
make the correctness test pass
do not use the large "score" buffer; now without non-max suppression OpenCL FAST is pretty efficient
finished OpenCL port of ORB
fixed bug in FAST
fixed extra whitespace
Fixed getPolicy() method to make it thread-safe.
Merge pull request #2474 from akarsakov:fix_getpolicy
fix for unsupported doubles
Merge pull request #2480 from vpisarev:ocl_orb
Merge pull request #2482 from ilya-lavrenov:tapi_fix
TAPI: added perf test for stitching
TAPI: stitching, replaced Mat->UMat/_Array
features2d: workaround for 'utrainDescCollection' issue (PR #2142)
TAPI: stitching: improve warpers
TAPI: stitching: workaround for problem getUMat() call
TAPI: stitching: optimize exposure
TAPI: stitching: optimize compare operation
stitching: use BORDER_CONSTANT in warp
stitching: extend logging