Merge branch 'unstable' into DA-406

* unstable:
  <DA-404> add gps check before starting
  update UI on main thread
  (iOS) highlight timeline tab when timeline is changed
  small refactorings
  fixed some typos
  removed dialog on Android
workaround for bogus "cancel" button in navigation bar of twitter authorisation screen
Merge branch 'DA-406' into unstable

* DA-406:
  workaround for bogus "cancel" button in navigation bar of twitter authorisation screen