Bug 1007847: Migrate creation date for links.

Pulls the creation date for links during the migration process. Changes
the created field to use default=timezone.new instead of auto_now_add
so that the created date can be set when a link is created and not
overridden.

Also fixes an incorrectly frozen spec for the links table in order to
make schemamigration behave properly.
Change collect_ga_data to collect data for two days ago by default.

Since GA takes up to 24 hours to show collected data, we should run the
collect command after midnight to be able to collect data for every 
click from 24 hours ago. This means it should collect from two days ago
instead of yesterday.
Add 'today' as a valid date for the collect_ga_data command.

This will allow the dev server to collect data for the current day to
speed up testing.
Fix bug 1008431: Do not prefetch banners on user profile page.

For some reason I don't fully understand, prefetching banners related to
banner variations for a user's links causes some banners to not be 
fetched and raise DoesNotExist instead. I imagine it has something to do
with banner variations being a GenericRelation.

This adds some queries to the profile page, but they're pretty cacheable
by django-cache-machine.
Bug 1008431: Remove another prefetch_related bug.
Remove need for slash at the end of legacy referral urls and fix locale.
Never cache the link referral view.
Change URL for link detail page to avoid conflict with legacy referrals.
Fix bug 1007855: Display URL instead of "Website" on leaderboard links.
Fix bug 1009346: Do not escape special characters in banner URLs.
Bug 1008999: Disable collecting data from GA, track clicks manually.

We’ll keep GA collecting data so we can compare it to our manual data 
and see what’s up.
Bug 1008447: Add CachingMixin and CacheManager to User class.

When a new link is created, the cached results for a user’s links
doesn’t get invalidated because, while the link has a foreign key to the
user, the user isn’t cached by django-cache-machine. By adding the mixin
and manager to the user class, when a new link is created, the user, and
thus it’s related links, should be invalidated, fixing the caching 
issues on the dashboard.
Avoid count query in stats display to avoid caching.

Since all the pages the stats are included on already use the user’s
link_set, the results are cached (yet up to date due to invalidation) 
and don’t add any queries.
Add New Relic code to WSGI file.
Styling for old versions of IE
Bug 1005946: Ignore links that point to nonexistent users.
Add temporary command to deploy script to run via chief.
Remove temporary command from deploy script.
Do not run prime_app anymore, it should be unnecessary.
Fix the manager for Category and fix the validation.

The manager for Category now inherits from CachingManager and 
MPTTManager, whereas before it was only using CachingManager, causing
MPTT-related things to fail.

The validation now accounts for edge cases it previously missed, such as
assigning a parent to category that already has children or assigning
a parent that is not a root node. Previous reliance on get_level failed
when parents were assigned but the new level hadn’t been computed yet.