Enable "useProvidedKeypoints" flag on cuda::ORB's detectAndCompute function in order to able to describe provided keypoints.

* additional author : Ender Tunç <endertunc@yahoo.com>

resolves #6473

 * Enable "useProvidedKeypoints" flag on cuda::ORB's detectAndCompute function in order to able to describe provided keypoints.

   Update for using 'const' reference to avoid array copy on each iteration.

resolves #6473

	Update for 'const' reference to avoid array copy on each iteration.

  * modify test, too

Command line generation routine uses "-isystem" to include headers outside of "<opencv>/modules" folder, but GCC 6 does not work when passed "-isystem /usr/include" option.

  * fix issue 6521
  * use correct comparison

All of these: (performance) Prefer prefix ++/-- operators for non-primitive types.
[modules/calib3d/src/fundam.cpp:1049] -> [modules/calib3d/src/fundam.cpp:1049]: (style) Same expression on both sides of '&&'.

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

Root cause: when calling imread to read the pgm file, when returning with success reading file, the destructor will free the resource which used by memcpy, but in the code, the resource calculation was not correct, therefore, it will cause memory corruption during resource free.