OCL: matchTemplate

**Description:**
* used `float` instead of `int` for `CV_8U` in sumTemplate
* new block size for `dft`
* added `dft` for all platforms

Performance report:
http://ocl.itseez.com/intel/export/perf/pr/3013/report/

check_regression=*OCL*MatchTemplate*
test_modules=imgproc
build_examples=OFF
are you sure that `CV_32F` should be used for `CV_64F` too?