Prepare Downhill Simplex for pull request

This is an implementation of so-called downhill simplex method
(https://en.wikipedia.org/wiki/Nelder%E2%80%93Mead_method)

Please, let me know if you have any comments, whoever you'd be.
Started working on primal-dual

So far it does not even compile.
Merge branch 'optimPD' of github.com:nailbiter/opencv into tracking_api