Publish a New Version

[mbleigh]

Note: See divshot/ele-api#5 for specifics of the API calls for this.

Devs should be able to click a button to open a dialog to publish a new version. When they click the button, they should be prompted for a version number (and shown the latest published version number as a point of reference).

Submitting the new version successfully should result in a confirmation dialog with links to the public page URL for the new version as well as a link to the Gist (at the correct SHA) for the new version.