feature(build): Pre-build static pages and CSS for each locale.

* Generate copies of static pages for each locale. Replace links to localized resources (like CSS) with their prebuilt equivalent.
* Generate one CSS bundle per locale. The CSS bundle will contain the correct fonts for the locale.
* Serve up the css files based on the user's language.
* Add all locales to the default list of supportedLanguages so production builds can occur before production.json is created.
* Add rev cache-busting to web fonts.

Tangential changes:
* Alphabetize the bower dependencies.
* Run `selectconfig` grunt task earlier. selectconfig adds the server configuration under the `server` namespace in the grunt config.
* Add `configure_connect_fonts` which configures the languages to use in the `connect_fonts` task.
* Add a 'helper' configuration item: `are_dist_resources` - returns `true` if using dist resources.
* Add `i18n.normalizeLocale` and `i18n.normalizeLanguage`
feat: Add front end metrics gathering.

* Use SpeedTrap to collect client side metrics
* Add screen views and errors to an event stream.
* Metrics are sent to the `/metrics` endpoint on document unload or after 10 minutes of inactivity.
* Data that is sent to the backend is filtered - only data we expect is sent.
* Data collection sample rate is set by server configuration.

Other logged events:

* users who cancel login from the browser.
* complete_reset_password:link_damaged
* complete_reset_password:link_expired
* complete_signn_up:link_damaged
* confirm:too_many_attempts
* confirm:resend
* confirm_reset_password_resend
* login:canceled

Others changes:
* AuthErrors.toMessage now accepts `forceMessage`
* Change AuthErrors.toCode to accept an error object.
* Give `Session expired` an error code of 1002.

issue #1119
Merge pull request #1092 from mozilla/fonts-again-pregenerate

fix(l10n): Generate per locale CSS files that include the correct font subset for the locale.
Merge branch 'metrics'

Conflicts:
	server/config/awsbox.json
fix(build): Exclude testing tools from production build