Squashed 'extern/common/' content from commit 5844c46

git-subtree-dir: extern/common
git-subtree-split: 5844c4627682f009fff8fc048793879c0f0a3064
Merge commit 'af3aa666e3643967b43d76530cb9f93a46409e1f' as 'extern/common'
Add script for pulling in changes from external repos
Temporarily remove extern stuff.

I'll bring it back once we're actually going to use it.
Move stripe directory into "lib/" which gets copied back into place
by grunt.
Add mailchimp API wrapper
Show available commands on the admin dashboard.
Part 1 of changing the way secrets are stored
Second part of the transition.

The "Secrets" singleton can now always be retrieved by querying for a
fixed key, and it's much easier to add new properties.
Add mailchimp creds to the secrets model
Remove people only missing targeting data from the admin page
Sort by descending amount
Revert "Initial mail chimp stuff"

Will add it back in slightly different form.

This reverts commit ebd5711f8813a084776dcd27bcbaa84139a057ba.
Merge branch 'master' into mailchimp