Make sure CDX file is sorted.
fixes #441
Adjusted language of "live site preview unavailable message." Now doing a better job of
pointing the user to the archives or to the original site in a new window.

fixes #199
We were not allowing scripts to be run in iframe. fixed.
Also added our newer (and better) "no iframe preview" message as our default message in the iframe element in case nothing gets loaded.

fixes #237
We weren't sending the user agent when getting the title of the page.
Now sending the user agent. fixes #376
Updated weekly stats script to generate slightly altered list of stats for parnters list.
We should obviously clean this up in the future. it's till a little raw.
Fixes #435
Moved logging setting to settings_common. If we need to change that setting, we
should just overwrite it in settings.py

fixes #436
Copy editing on single link preview message
A little copy editing in weekly stats script
Updated stats for weekly hits numbers
Added a (somewhat clumsy) polling mechanism to the create link page. Now you
get a spinner until your screen cap is created. We poll to check for completion
every two seconds. Our create JS is getting pretty crufty. We should clean it
and the related templates in create-link.

fixes #446
bug fix: Now that we're generating the screen cap async, we need add a "loading"
state (spinner with non-clickable tab) to the single link view. fixed.

The spinner and pending logic on the single link page are pretty crufty. Way
complex. We should do a bit of refactoring in that view.
Users can now edit titles of links. Fixes #391