Add documentation for Kernel::run

Add OpenCL  support to linearPolar & logPolar.
The OpenCL code use float instead of double, so that it does not require
cl_khr_fp64 extension, with slight precision lost.

Add explicit conversion

Add explicit conversion from double to float to eliminate warning during
compilation.

Allow configuration of the square size in stereo_calib.

https://github.com/Itseez/opencv/issues/6456

Commits:
67fe57a0 add fixed video
db0ae2ca Restore 2.4 source branch for bug fix 6317.
97ac59cb Fix a memory leak indirectly caused by cvDestroyWindow
eb40afa2 Add a workaround for FFmpeg's color conversion accessing past the end of the buffer
421fcf9e Rearrange CvVideoWriter_FFMPEG::writeFrame for better readability
912592de Remove "INSTALL_NAME_DIR lib" target property
bb1c2d71 fix bug on border at pyrUp

image.forEachWithPosition does not exist