procedure; better window functions for some FFTs, resulting in
better decoder performance; User-selectable colors for backgrounds
of decoded messages. NB: more testing is desirable!
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@4951 ab8295b8-cf94-4d9e-aec4-7959e3be5d79