Change Imgproc_ prefix to Photo_ in all accuracy tests of photo module
Add test for issue #2646
Fix integer overflow in NL-Means denoising on white input

Issues #2646
Improve error reporting of JPEG image encoder

OpenCV issue #2604

After this patch applied an attempt to encode empty images produces exception
saying "Raw image encoder error: Empty JPEG image (DNL not supported)"
Removed obsolete steps from Windows installation tutorial (bug #2550)
Fixed formula of YCrCb to RGB conversion (bug #2725)
Fixed cheatsheet for loop (bug #2701)
Resolve warning in OpenCV Library project in Eclipse (Bug #2714)

Warning in auto generated code was suppressed by project settings.
Merge pull request #343 from taka-no-me:fix_nlmeans_2646
Merge pull request #344 from taka-no-me:improve_jpeg_encoder_errors
Merge pull request #345 from Daniil-Osokin:bugfix_2550
Merge pull request #348 from Daniil-Osokin:bugfix_YCrCb_formula
Merge pull request #349 from Daniil-Osokin:bugfix_opencv_cheatsheet
Merge pull request #350 from asmorkalov:android_java_warnings