trackback 4.7.x-1.1

Fixed the following bugs and features:

#16239 Not execute the auto-detection for unpublished nodes.
#22764 Character encoding.
#32725 The module doesn't accept MSN trackback urls.
#45003 disable trackbacks on a per node basis.
#73416 Old db files deleted and prefixed tables working.
#73637 Correct usage of url() and l() with fragments.
#77018 Bugfix: excerpt does not truncated.
#82007 list trackbacks in reverse chronological order by default.
#88389 Fixup db tables.
#90454 the /admin/help/trackback need to be update.