Add hooks to AF that allow altering User and Title specific vars

Added two hooks to the AbuseFilter, one that allows altering of the
variables created for a specific user and one for title specific
variables. This a much cleaner way to add title or user specific
variables than using the current general-purpose hooks.

Change-Id: I7374846346dd220b5d0633c11c134030f98bcf00
Merge "Add hooks to AF that allow altering User and Title specific vars"