wiki: Ensure wiki page not found gives a 404.
wiki: Ensure users who cannot revise do not get a create link.
wiki: unsafe() diff html on conflict.
wiki: Fix an xss fixed server side already.
wiki: Allow dashes in page names.
wiki: Ensure spammed users cannot create pages.
wiki: Add page name to title.
wiki: Add wiki page name to body class.
traffic: Add campaign_history for querying targeting things.
PromoteReport for generating traffic reports on promoted links.
Submit page subreddit suggestion obeys user's over_18 preference.
Show gold creddit balance even if user doesn't have gold.
pagecache: Do not write 304s to the cache.

304s are triggered in reddit by the value of a request's
If-Modified-Since header. This header is not accounted for in the
request_key. We mustn't cache a response that isn't necessarily valid
for that request.
pagecache: Make actions able to specify pagecache policies.

This allows us to control pagecache behaviour at a per-action level.
There are three policy levels,

LOGGEDIN_AND_LOGGEDOUT - allow caching of resp. generated for loggedin.
LOGGEDOUT_ONLY - the current default.
NEVER - don't use the pagecache.
pagecache: Don't cache GET_info.

Most of these results are negative lookups, so we end up spending a lot
of memcache bandwidth and memory space on identical json responses.
pagecache: Add a debug header to indicate hits/misses.

To get the header in responses, be in debug mode or send
"Pragma: x-reddit-pagecache" in your request.
Add support for a live-config sidebar info message.
Skip over Ads with 0 weight
Revert "Remove memoize on normalize_hot."

This reverts commit 1dbc2b181a463828a0eda76551a1e1d1b31afeb5.
If a user is loggedin, and does not have over18 pref, do not show over18 content.

Previously, the existence of an over18 cookie would display over18 content to
loggedin users, even if their preferences disallowed over18 content.