cups security and bug fix update

1:1.3.7-30 - Backported patch to fix transcoding for ASCII bug 759081, STR 3832. 1:1.3.7-29 - The imageto filters could crash with bad GIF files CVE-2011-2896, STR 3867, STR 3914, bug 752118. 1:1.3.7-28 - Web interface didn't show completed jobs for printer STR 3436, bug 625900 - Serial backend...