Email drafts; UI changes slightly updated.

@jrburke @kgrandon

This is derived from https://github.com/KevinGrandon/gaia/compare/master...bug_834646_local_drafts

Unfortunately, with the changes to the back-end built files or something like that, my attempt to rebase failed, so I just created a new branch and checked out the files from that branch that weren't backend.

I've integrated the contents of https://github.com/mozilla-b2g/gaia-email-libs-and-more/pull/171 install-into-gaia into it.

I am stepping out for dinner.  There may be some bugs in this UI part of it, I haven't actually run with it yet, but the unit tests are so good, it must work, right? ...  Be back soon.