Need shortened URLs for Stori sharing

[robbear]

See https://github.com/BlueRival/node-google-url/blob/master/lib/google.js for example of using Google API.

Plan:

1. Convert Stori URL to GoogleShort. Use in sharing/email. This implies an Ajax call to the server from the client, and gives us an opportunity to track usage.
2. Handle GoogleShort in node.js server. Expand to Stori URL.