Bug 981676 - Backout progress bar refinements from bugs 980438/962103 (r=mfinkle)
Bug 982893: give up on not trying to initialize Weave.Status on window open, since we were failing at it anyways, r=markh

Changes:
 * don't try to avoid loading Weave.Status modules on window open
 * access the authManager via Weave.Status instead of Weave.Service, since Weave.Status will already be initialized in almost all cases.

--HG--
extra : rebase_source : a328609e5c5c461fb92b050b8d34816f08f01d8a
Bug 982241: make the UI observe weave:service:setup-complete so that it gets updated correctly when re-signing in after an auth error, r=ttaubert

Changes:
 * start observing weave:service:setup-complete to update the UI after all logins (re-auth, initial sign-in)
 * stop observing FxAccountsCommon.ONLOGIN_NOTIFICATION, since the state we depend on to update the UI never changes interestingly as a result of it firing

--HG--
extra : rebase_source : 8632d597557b7a25ebc31dd53ad5680ac5a72583