Let install view manage the connection to the provisioning socket as
well as cleaning up the window on completion, simplifying options.js.
Call `remove` so that the view stops listening when the window closes.
Move view script and template to background page.
Adds ability to hide nav if this isn't our first run.
// FREEBIE
* Move install flow i18n logic to install_view.js (from options.js)
* Switch to using placeholders (instead of jQuery) for i18n messages with html.
* Switch to using moustache template instead of jQuery for i18n substitution.
// FREEBIE
* Refactor options.js into a view
* Break up install flow into a series of screens
* Remove bootstrap
* Make installer window static size, mostly to facilitate positioning
// FREEBIE
