ocl_calcOpticalFlowPyrLK optimizations

1. decrease branch number in CL code by replacing them into weights
2. decrease local mem pressure in reduce operation by using private variables
3. decrease image sampler pressure by caching data into local memory
4. remove unnecessary sync point on the HOST side.
Update out.cpp

Fixed a bug with the cv::format(cv::Mat, ...) method for matrices with only one row

see http://answers.opencv.org/question/21201/cvformat-does-not-format-the-way-it-should/?answer=23945#post-id-23945 for details
increase epsilon for MOG2::getBackgroundImage test:

it uses float arithmetics
Merge pull request #2541 from JinoBetti:2.4
fixed C4505
doc typos
Merge pull request #2548 from jet47:gpu_mog2_test
Merge pull request #2551 from ilya-lavrenov:ocl_nonfree
Merge pull request #2553 from ilya-lavrenov:typo
OpenCV version++. OpenCV Manager version++.
Merge pull request #2554 from asmorkalov:ocv_249_version
Added IPP Async converters, doc and sample
Added SharedMatrix
disable gpu::GeneralizedHough compilation on gcc 4.7
Merge remote-tracking branch 'github/master' into pullreq/140319-PyrLKOpticalFlow

Conflicts:
	modules/video/src/opencl/pyrlk.cl
disable GeneralizedHough tests on gcc 4.7
Merge pull request #2572 from jet47:gpu-generalized-hough
Merge remote-tracking branch 'origin/2.4' into merge-2.4

Conflicts:
	modules/core/include/opencv2/core/version.hpp
	modules/core/src/out.cpp
	modules/cudaimgproc/test/test_hough.cpp
	modules/gpu/doc/introduction.rst
	modules/gpu/perf/perf_imgproc.cpp
	modules/gpu/src/generalized_hough.cpp
	modules/nonfree/perf/perf_main.cpp
Fix ifdef for IPP version greater 8.1
Fix for pullrequest comment