Add rc.unpatrolled to the recentchanges API

Add rc.unpatrolled to the recentchanges API

On SpecialRecentChanges, the unpatrolled "bang" icon is only
rendered when:
- the user has the patrol right.
- the rc type is EDIT and rcpatrol is permitted, or
  the tc type is NEW and nppatrol is permitted.
- the rc event is in fact still unpatrolled.

In other words, when an edit is patrollable and unpatrolled.

However, consumers of the API are unable to render this because
the API only has a boolean "patrolled" attribute. Apps using
the absence of "patrolled" and presence of "patrol" right as
meaning "unpatrolled" get into trouble on wikis with RCpatrol
disabled and NPpatrol enabled. In those cases the app would
render a change as unpatrolled, but when the user clicks it
find out it can't be patrolled.

This adds an "unpatrolled" flag that does just that.

Change-Id: Ic947c6c75eb7936fcebdccbcd27ff62e07f1feda