New actions, filters & UX

* Change virtually all existing filters
* Change actions "feature" to "useful" and "hide" to "inappropriate"
* Introduce action "non-actionable"
* Change the UX:
  * Now only 1 of the 4 editor tools (useful, resolved, non-actionable, inapropriate) can be performed at once
  * After having flagged on of those 4, "undo" button pops up as well as the details of the previous flag
  * Only after flagging as inappropriate do oversight-related tools pop up
  * Moderation actions are 1-click, with possibility for flyout window to leave comment afterwards

PS25: bsitu's feedback
PS29: kaldari's feedback
PS32: bsitu's feedback

See requirements at http://www.mediawiki.org/wiki/Article_feedback/Version_5/Feature_Requirements#Simpler_moderation_tools

Change-Id: Ibf97654b0d9344fd89e0c8b3377fa821fdc9043f