We set `I18n.locale = :en` before each test, and so creating a new card
will automatically create English translations.
So visiting the Spanish page won't show the card, since no Spanish
translation exists for it. If we visit the klingon page after doing so,
the last used locale (Spanish) will still be used, and so the test will
fail.
Specifically creating Spanish translations instead of the English ones
makes the translations visible when visiting the Spanish homepage.
* Store the last used locale in the session
* Allow home page to be identified in helpers even when containing
parameters
* Create initializer to explicitly set the available locales, the
default and the load_path
