More rework of feed item list to deal with missing feeds.
Merge remote-tracking branch 'upstream/master'
More error handling improvements.  Added developer debug mode.
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Switch mark-unread task to use story hash.
Change save-story to use story hash.
Changed the read later success confirmation to use the checkmark HUD instead of an alert view.
Merge branch 'offline'

* offline:
  Adding preferences for offline story limit and image download concurrency.
Trimming river URL by allowing 'f' to be used as a feed id parameter.
Fixing iOS crash on empty unread stories by providing correct data structure. Thanks to @linnet for spotting the bug.
Merge pull request #360 from linnet/hud-notifications

iOS: Use checkmark HUD instead of alert view when posting to read later service
Merge pull request #364 from ojiikun/master

Android: Bugfixes
Merge branch 'master' into offline

# By ojiikun (4) and others
# Via Samuel Clay (4) and ojiikun (3)
* master:
  Fixing iOS crash on empty unread stories by providing correct data structure. Thanks to @linnet for spotting the bug.
  Trimming river URL by allowing 'f' to be used as a feed id parameter.
  Changed the read later success confirmation to use the checkmark HUD instead of an alert view.
  Change save-story to use story hash.
  Switch mark-unread task to use story hash.
  More error handling improvements.  Added developer debug mode.
  More rework of feed item list to deal with missing feeds.