Update to 2.15.2

ChangeLog:
  http://git.finalrewind.org/feh/plain/ChangeLog

Sat, 16 Apr 2016 18:32:38 +0200

* Release v2.15.2
    * Fix --keep-zoom-vp not keeping the viewport x/y offsets (broken by 2.15)

Fri, 15 Apr 2016 10:18:37 +0200  Daniel Friesel <derf+feh@finalrewind.org>

* Release v2.15.1
    * Fix w (size_to_image) key not updating window size when --scale-down
      or --geometry is active

Sat, 09 Apr 2016 20:42:23 +0200  Daniel Friesel <derf+feh@finalrewind.org>

* Release v2.15
    * Patch by William Woodruff: Add --insecure option to disable HTTPS
      certificate checks
    * Patch by guraga: Add --no-recursive option to disable recursive directory
      expansion.  Note that --no-recursive is the default behaviour of feh.
      This option is mostly useful to override a --recursive set in a theme or
      shell alias
    * Patch by Richard Molitor: Improve --scale-down in tiling environments.
      This fixes flickering when changing images at the cost of slightly
      less apaptive scale-down behaviour: Window size changes are now only
      processed when the active image is changed
    * --action and --action[1..9] now support action titles
      (e.g. --action '[some title]some-command %F'), which are displayed
      instead of the specified shell command. Note that the title must not
      start with a space. Titles starting with a space are treated as part of
      of the command so that actions like '[ -L %F ] && foo' still work


(szptvlfn)