Removed unused variable dst.
MPlayer now exits if it is unable to create a file for JPEG output and prints
an appropriate message, instead of going on if all is right (which is not).
Added line to authors file.
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@13253 b3059339-0415-0410-9bf9-f77b7e298cf2