Call loop closure on the first frame

Previously loop closure was only called after the first match
(the second frame), which caused the initial reference frame to
be the second frame, not the first.  This resulted in the
homography file being off by one.
updated release notes
Merge pull request #8 from mleotta/dev/fix-closure-ref-frame

Dev/fix closure ref frame
Merge pull request #9 from Kitware/release

Release