Fix a bug of retinaParameters.
When colorMode is set to 0 via Retina::_init method, _retinaParameters's
colorMode variable is not correctly assigned.
Added MOG and MOG2.
Resolved a compiling error under Linux.
Resolved a compiling warning under Windows.
Resolved compiling errors under Linux.
Used perf_precomp.hpp instead of precomp.hpp for test.
Merge pull request #4 from Itseez/2.4

OpenCV changes
Fix bilateralFilter function
Optimized mog and mog2, which have much better performance.
Make some tweaks to make `sum` operations less frequently
Fix build error.
Remove trailing whitespace.
rewrite gpu stereo multi gpu sample:

* use different approaches -> threads and streams
* clean up code
fixed building OpenCV with IPP 6.x (different DFT API); added Canny and rectangular morphology (based on Alex Kapustin patches)
fixed bugs in rectangular morphology case
Removed the trailing whitespace
Removed trailing whitespace
Removed whitespace.
Added perf namespace.
Removed performance test.