FIX: Sharing link stood visible after using browser’s back button
Merge pull request #2981 from karreiro/share_bug

FIX: Sharing link stood visible after using browser’s back button
FEATURE: roll up function for 123.456.789.* ranges
FIX: Mailing list mode was not checking for user deleted posts
moar camelCase
FIX: limit other accounts deletion to 50 accounts otherwise it'll feel too slow
FIX: Admin panel referral stats not counting topics correctly

Due to what seems to be a bug in ActiveRecord, the distinct: true option
is not recognized on counts with string column names. This commit fixes
that by moving the DISTINCT into the count string.

For robustness, the integration spec for IncomingLinksReport was
rewritten to be an actual integration spec, running the actual interface
on actual fake data.