Add back Mailchimp

Mistakenly taken away in Commit #5f15836077
Replaced deprecated Search API methods
Merge remote-tracking branch 'origin/double-vision'
Offloaded indexing from main post_put method to taskqueue

Did this to speed up datastore puts and get a response back to the user
faster
Merge pull request #65 from rhefner1/offload-indexing-to-taskqueue

Offload indexing to taskqueue