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
No, but this function used only for CV_8U and CV_32F