Fix for issue #3645 (http://code.opencv.org/issues/3645).
Implement missing features in CvCaptureCAM_VFW class.

Implemented missing CvCaptureCAM_VFW::setProperty() member function (handling CV_CAP_PROP_FRAME_WIDTH, CV_CAP_PROP_FRAME_HEIGHT, CV_CAP_PROP_FPS properties).
Extended CvCaptureCAM_VFW::setProperty()/getProperty() functions to handle also CV_CAP_PROP_FPS property.
Minor refactoring of CvCaptureCAM_VFW class.
Merge pull request #2640 from a-wi:2.4
IPP: CV::dft
Documentation - minor fix-ups
Added parallel version for DFT_ROWS
ipp: added LUT optimization
Added ippiComputeThreshold_Otsu to cv::threshold
Fix problem with sanity check of transform ecc with ipp resize
Added setIppErrorStatus()
Merge pull request #2659 from adrians:docs_pull_1
Changed epsilon for hog test, because hog detector is sensible to resize accuracy.
Merge remote-tracking branch 'origin/2.4' into merge-2.4
Merge pull request #2668 from vbystricky:perf_TransformECC
Merge pull request #2675 from SpecLad:merge-2.4
fixed compilation
Merge pull request #2674 from akarsakov:ocl_hog_fix_epsilon
Merge pull request #2654 from ElenaGvozdeva:ipp_DFT
Merge pull request #2653 from alalek:ipp_lut
IPP: cv::dft fixed
Merge pull request #2677 from ilya-lavrenov:ipp_compilation