Fix issues introduced by some merges.

Activate HTML5 mode exclusively when actually running in the context of the
application by introducing a `prx.base` module which acts as the application
module in the HTML and nowhere else.

Mock out some additional `$state` information as required by
https://github.com/angular-ui/ui-router/commit/71cad3d636508b5a9fe004775ad1f1adc0c80c3e#diff-544b7ce9751e1a566e17d486dd4ab576R87