PromoCampaign: make location_str property.
Add location to PromotedLinkTraffic table.
Use constant_time_compare for checking webhook secrets.
Add 'expired' noop event for CoinbaseController.
Fix ValidCard validator.
Fix "-->" appearing in IE<8 due to conditional comment syntax.
CSS Filter: Add some more properties.

https://developer.mozilla.org/en-US/docs/Web/CSS/pointer-events

https://developer.mozilla.org/en-US/docs/Web/CSS/image-rendering
https://developer.mozilla.org/en-US/docs/Web/CSS/image-resolution
https://developer.mozilla.org/en-US/docs/Web/CSS/image-orientation

http://www.w3.org/TR/css3-grid-layout/
Thing: Add __setstate__ method.

Special handling for unpickling is moved out of __getattr__ and
explained better now.
Thing: Delete non-functional _asked_for_data.

Was attempting to check whether Thing._byID had requested data
attributes, but was always set to True by the constructor.
Thing: Remove commented out code.
Thing: Cleanup and simplify __getattr__.
Thing.__getattr__: don't be so careful about getting _essentials.
Thing: replace log_text with g.log.error.
Don't ratelimit comments by users on their own promoted links.
Only put campaigns in underdelivered query if they were charged.
Reset campaign to unauthorized state when its authorization hold expires.
Subreddit ban list JSON: Add timestamps
Subreddit settings: update allow_top label
site_admin: Remove mergability.

This removes the prev_ fields in Subreddit.

This fixes the problem of drift if there is an error
between the wiki revision and Subreddit commiting.
/about/mod: Revert to old sorting behaviour.