new corner refinement method :: using the contour-lines (#973)

* doCornerRefinement to CornerRefinementMethod :: detected contours points are used to detect the corners

* some little corrections

* samples edited

* documented :)

* tabs corrected

* Docu corrections

* refinement for all candidates

* refinement for all candidates :: copy paste error corrected

* comment

results in less code and more consistent parameter handling.

allows using Mat and vector<Vec3d> as argument for rvecs, tvecs that are
allocated at once.