Update precomp.hpp
Update hough_circles.cpp
small changes in hough circles tutorial
Update cap_ios_abstract_camera.mm

AVCaptureVideoPreviewLayer setOrientation is depricated. This fixes the warning and provides backward compatibility.
Merge pull request #2343 from yashdv:template_matching_doc_fix
Merge pull request #2339 from jet47:gpu-warnings
Merge pull request #2354 from gleb-sternharz:Branch_2.4.8
Merge remote-tracking branch 'origin/2.4' into merge-2.4

Conflicts:
	modules/core/src/gl_core_3_1.cpp
	modules/core/src/opencl/convert.cl
	modules/cudaimgproc/src/cuda/canny.cu
	modules/cudastereo/perf/perf_stereo.cpp
	modules/gpu/perf/perf_imgproc.cpp
	modules/gpu/test/test_denoising.cpp
	modules/ocl/src/opencl/imgproc_resize.cl
	samples/cpp/Qt_sample/main.cpp
rotRect using points
Merge pull request #2340 from ilya-lavrenov:tapi_lab
Fixed compilation with IPP on Linux. Added linking with Intel compiler runtime libraries.
Added more colorizing options to XLS generating script
fixed warnings
Merge pull request #2334 from alalek:umat_usage_flags_2
removed tabs
Merge pull request #2345 from ilya-lavrenov:tapi_3cn_perf
Merge pull request #2346 from ilya-lavrenov:umat_tests_cleanup
fixed year in copyright
fixed incorrect code in introduction tutorial
removed unused field