data_t helper and config/locales/data.en.yml

Localizes:
  - script.name
  - game.name
  - trophy.name
  - concept.description

Big item remaining:
  - level.instructions
Factor out footer partial
Localize footer
Strip whitespace from accepted languages in some browsers
Localize teacher tools and a bit more
Merge branch 'master' into data_i18n

Conflicts:
	app/views/layouts/application.html.haml