Merge branch 'master' of https://github.com/mnb20/k-9 into pull111

* 'master' of https://github.com/mnb20/k-9:
  High DPI version of archive button icon
  Fixed whitespace
  Remove TODO
  Replaced archive icon. Still a bit crap, but better than my previous attempt.
  Added batch buttons for Archive and Move. Made batch buttons configurable.