Handle 'Failed' and 'Denied' PayPal IPNs.

These are noops and can be ignored.
Add goldloggedin as a user type in GA custom variable.

This change will let us segment users by gold membership.
Be consistent with cache_chain names
Ratelimits: Recover if the incr fails

For a miniscule number of requests, the old value
in memcache will fall out after the call to `add`,
but before the call to `incr`. This change recovers
from that scenario.
Add sample_rate param to Stats.event_count
Add stats tracking to sitewide ratelimiting
Don't double ratelimit error responses
OAuth2: Add /api/v1/me/prefs endpoint

Returns the logged in users preferences
Supports a 'fields' parameter for limiting the
response to the desired fields.
Refactor /post/options for re-use

* Create a var with the validators
* Don't always grab langs out of request.POST
* Refactor validation to a separate function
Add PATCH /api/v1/me/prefs endpoint

Allows partial update of the user's preferences
/dev/api: PATCH endpoint with JSON model support
Scraper/Websockets: Small cleanup of debug messages, dev config.
Do not incr_counts for links if item.is_author.
OAuth: Fix APIv1Controller's handling of missing tokens
OAuth: Allow use of captchas

Add support for "scopeless" oauth 2 endpoints,
set captcha endpoints to be scopeless.
/dev/api: Fix docs for /api/v1/me/prefs
Refactor "allowed_scopes" -> "required_scopes"

This makes it more clear what the parameter does.
/dev/api: Reorder decorators so 'view code' points to the right place
trophy: Add trophy listing api.
karma: Add karma list api endpoint.