Remember me and offline awareness

Branch is no longer well-named as it is using localStorage via the settings collection, not an AccountManager plugin.

This is a pretty big PR as it has a few pieces. There is a missing piece or two, but I wanted to get this pulled in and tested.

1. Remember me UI and functionality (UI has been added to both the login screen and settings).
2. Remember me auto-login (when the user has chosen it)
3. Offline awareness (better timeouts, warnings, etc) and the menusheet now responds to being offline by limiting choices to what might actually work

There is at least one bug that I am trying to track down related to the settings screen and offline... but I can't work out the steps to reproduce yet.

MOST importantly, we need a warning screen that tells the user the risks of using the remember me feature as it currently stands (don't lose your phone, don't root your phone, etc). I will make a ticket in Trac to get someone to write the copy for this and add it when we have it.