Comment ipp version of CV_BGR2GRAY color convertion, by problems in BRIEF accuracy test and Path_Idx_Cn_NPoints_WSize perfomance test

Enable ipp MeanStdDev calculation for 32F_C1 images. Decrease accuracy sanity check of the perfomance test

Canny uncommented, prefix of ipp function changed. Ipp version of Canny called only for images with one channels

Change deprecated function ippicviMulC_32f_C1IR to ippicviMulC_32f_C1R. Check results of ipp function, if error was return run opencv branch of code

When compiling without OpenCL, some classes from its namespace are still used in code.

Conflicts:
	modules/imgproc/src/opencl/integral_sqrsum.cl
	modules/nonfree/doc/feature_detection.rst
	modules/nonfree/include/opencv2/nonfree/ocl.hpp
	modules/nonfree/src/surf_ocl.cpp
	modules/nonfree/test/test_features2d.cpp
	modules/ocl/doc/image_processing.rst
	modules/ocl/include/opencv2/ocl/ocl.hpp
	modules/ocl/perf/perf_imgproc.cpp
	modules/ocl/perf/perf_match_template.cpp
	modules/ocl/src/haar.cpp
	modules/ocl/src/imgproc.cpp
	modules/ocl/src/match_template.cpp
	modules/ocl/src/opencl/haarobjectdetect.cl
	modules/ocl/src/opencl/haarobjectdetect_scaled2.cl
	modules/ocl/test/test_imgproc.cpp