Log Message:
Update to 3.20160509. From the changelog:

  [ Amitai Schlair ]
  * img: ignore the case of the extension when detecting image format,
    fixing the regression that *.JPG etc. would not be displayed
    since 3.20160506

  [ Simon McVittie ]
  * img: parse img_allowed_formats case-insensitively, as was done in
    3.20141016.3
  * inline: restore backwards compat for show=-1 syntax, which
    worked before 3.20160121
  * Remove a spurious changelog entry from 3.20160506 (the relevant
    change was already in 3.20150614)
  * Add CVE-2016-4561 reference to 3.20160506 changelog
  * Set high urgency to get the CVE-2016-4561 fix and CVE-2016-3714
    mitigation into testing

 -- Simon McVittie <smcv@debian.org>  Mon, 09 May 2016 21:57:09 +0100