Re-enable minification

[adborden]

Let's enable minification for production builds to get smaller bundles.

• enable ng-strict-di https://docs.angularjs.org/api/ng/directive/ngApp#!
• enable minification for produciton builds only
• make sure source maps are shipped to production

[adborden]

@KyleW would you mind updating this with what you think is left? I think we want to add a line to review these third-party libraries.