[geary] (7 commits) ...Merge branch 'wip/email-flag-refinement' into 'master'

[Michael Gratton <mjog src gnome org>]

Summary of changes:

  fb6e638... Treat ConnectivityManager errors as failure rather than unr (*)
  539893f... Add some unit tests for setting email flags (*)
  fa48f98... Explicity throw an error when requirements aren't met for s (*)
  4575f68... Ensure ImapDb.Folder.set_email_flag_async also works on del (*)
  438f74d... Pass a email id with a position when setting flags during a (*)
  7c05f5d... Throw the correct error when email id is not valid for crea (*)
  d188397... Merge branch 'wip/email-flag-refinement' into 'master'

(*) This commit already existed in another branch; no separate mail sent