Merge pull request #4 from Itseez/2.4

OpenCV changes
Fix bilateralFilter function
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
Add IPP support in compare function
Merge pull request #1345 from pengx17:2.4_tvl1ocl_opt
Merge pull request #1355 from jet47:gpu-stereo-multi-gpu-sample
Merge pull request #1302 from kdrobnyh:compare
Globbing accuracy test fail on Windows RT fixed.
Merge pull request #1385 from asmorkalov:winrt_glob_fix
Merge pull request #1300 from kdrobnyh:FilterBilateral