This is an implementation of primal-dual algorithm, based on the C++
source code by Vadim Pisarevsky. It was extended to handle the denoising
based on multiple observations. It also contains documentation and
tests.

it conflicts with cv::detail

changed default parameters in CreateERFiltersNM{1,2} functions. They are not needed now in the sample example.

This allows to get rid of the last remaining Ptr<T>::addref calls.

Also changed the static functions to inline, to stop GCC complaining
about unused functions.

Now the features2d class wrappers use composition instead of inheritance.