Both decoders now have slightly better performance and faster
execution. The rare "duplicate decodes" in JT9 were eliminated.
On Windows, at least, calls to f90 routine system_clock() do not
provide correct wall time increments. Changed to using secnds()
instead.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@4571 ab8295b8-cf94-4d9e-aec4-7959e3be5d79