[ticket/9550] Add template event in the footer of view topic pages

Adds a template event to bottom of view topic pages, under the
pagination and quick reply, but prior to any bread crumbs.
http://area51.phpbb.com/phpBB/viewtopic.php?f=111&t=43385
http://tracker.phpbb.com/browse/PHPBB3-9550

PHPBB3-9550
[ticket/9550] Add viewtopic_body_footer_before to the event docs

PHPBB3-9550
Further clarify doc for viewtopic_body_footer_before
[ticket/9550] cut doc entry to 79 cols
Merge remote-tracking branch 'VSEphpbb/ticket/9550' into develop

# By Matt Friedman
# Via Matt Friedman
* VSEphpbb/ticket/9550:
  [ticket/9550] cut doc entry to 79 cols
  Further clarify doc for viewtopic_body_footer_before
  [ticket/9550] Add viewtopic_body_footer_before to the event docs
  [ticket/9550] Add template event in the footer of view topic pages