Added support for comments on other sites than SO, added placeholders, fixed some bugs

[fastnlight0]

Added support for comments and Answer related NAA options for sites other than Stack Overflow.

In addition, similar to AutoReviewComments, I added 3 placeholders:

Placeholder	Description	Example
%SITENAME%	The site name	Stack Overflow, Super User, Physics Stack Exchange
%SITEURL%	The domain of the current site	stackoverflow.com, money.stackexchange.com
%OP%	The author of the question/answer	fastnlight

I've also fixed a bug where if a user was recognized in a collective, AdvancedFlagging would believe their answer was actually a question.