add cas support with a few tests
allow disabling of local logins.  In the instance where an .edu is using cas they may not want a user to be able to log in once the users credentials have been revoked in the system that feeds the CAS authentication server.  This is very optional
simplify, clarify TextSentinel

codeclimate pointed this out. I agree it is better
to simplify and reveal intentions.
small refactor of RateLimiter for clarity
extract TopicNotifier class from topic
minor refactorings
Make pry a bit more useful
Extract Topic#posters_summary
Remove unused parameters from posters_summary
Sliding window rate limiting

Switched the algorithm to use a circular buffer
based on a redis list
Merge pull request #899 from chrishunt/chrishunt/extract-topic-posters-summary

Extract topic posters summary
Merge branch 'refactoring' of git://github.com/mattvanhorn/discourse

Conflicts:
	lib/text_sentinel.rb
Bad merge. Oddly not caught by autospec.
FIX: Invited by link was broken on user activity.
Bounce the popup tips again when you click submit button again
Weigh staff likes higher when calculating scores. New site setting: `staff_like_weight`
can set the factor (default is 3)
Fix TopicPostersSummary when a suggested topic includes a user who has been deleted
FIX: Couldn't access "Uncategorized" category from category list.
FIX: Removes some duplicates in search results when the search context is a user.
keep French localization up to date

:fr: