Investigation to sequence

This was intended to use localization to let portals change jargon - in this case 'investigation' - to different jargon, in this case 'sequence'. Localizations were created on a per-theme basis and set based on the theme setting, falling back to 'en'.

While doing this, I also removed the `LocalName` module and moved the translations it supported into Rails' stock localization. I'm guessing that's a bigger change than the jargon translation, but `LocalName` is less widely used than it might appear and it came out pretty smoothly.

This is also described in https://www.pivotaltracker.com/story/show/52738161 and also covers a bit of this: https://www.pivotaltracker.com/story/show/52734437 .