templated std::vector<T> constructor was being called instead of const std::vector<cv::cuda::GpuMat>.

Rewrite linearPolar & logPolar so that they do not depend on the
deprecated API CvMat. Issue 6377 is resolved in this way because the two
routines do not convert UMat to CvMat anymore.

They were issued for every frame retrieved - even in a release build.

"Eat" unexpected backend exceptions

Added 2 inline functions in persistence.hpp
So that the '>>' operator works correctly for std::Vector<KeyPoint> and
std::Vector<DMatch>

- Allows using non-default device names such as /dev/v4l/by-path/pci-0000:00:1d.0-usb-0:1.1:1.0-video-index0

CvVideoWriter_GStreamer assumes a JPEG encoded stream if the height of
the given frame size is 1.