Fix SVM::trainAuto (Bug #4464)

Fixed errors in parallel_for based on pthreads

Fixing compiler errore & removing whitespaces

Fixing prallel_for_pthreads error and warnings on win

add template specialization Mat::push_back() for MatExpr paramters

extend push_back MatExpr to mat in unit test

cast to object instead of reference

test with multi-row MatExpr input

Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

Conflicts:
	samples/data/detect_blob.png

TODO: Make nosse ver faster than Sobel
      Make sse ver faster than Sobel for BORDER_REPLICATE

TODO: HAL-accelerated code

057cd52 first versions: cv::ogl::convertFromGLTexture2D & cv::ogl::convertToGLTexture2D
5656e94 added autogenerated stuff for cl_gl.h
765f1fd resolved CL functions in opengl.cpp
9f9fee3 implemented function cv::ogl::ocl::initializeContextFromGLTexture2D()
a792adb cv::ogl::ocl::initializeContextFromGLTexture2D() - added linux support (glx.h)
51c2869 added missing error message in function cv::ogl::ocl::initializeContextFromGLTexture2D()
513b887 fixed extension call in function cv::ogl::ocl::initializeContextFromGLTexture2D()
475a3e9 added CL-GL interop Windows sample (gpu/opengl_interop.cpp)
07af28f added building of CL-GL interop sample - Windows only
befe3a2 fixed whitespace errors & doxygen warnings (precommit_docs)
551251a changed function name to cv::ogl::ocl::initializeContextFromGL(), removed unused argument
4d5f009 changed CL_DEVICES_FOR_GL_CONTEXT_KHR to CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KHR
9fc3055 changed CL_DEVICES_FOR_GL_CONTEXT_KHR to CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KH
6d31cee Revert "changed CL_DEVICES_FOR_GL_CONTEXT_KHR to CL_CURRENT_DEVICE_FOR_GL_CONTEXT_KH"
cc6a025 added texture format check in cv::ogl::convertFromGLTexture2D()
063a2c1 CL-GL sample: added Linux implementation (Xlib/GLX)
c392ae9 fixed trailing whitespace
85a80d0 fixed include files
ae23628 excluded samples/opengl from build case 2
9870ea5 added android EGL support
530b64c added doxygen documentation comments to CL-GL interop functions