[geary] (14 commits) ...Merge branch 'wip/131-sent-mail' into 'mainline'

[Michael Gratton <mjog src gnome org>]

Summary of changes:

  d7006f3... Ensure the prefetcher considers all local email (*)
  ee11d0d... Allow sending NOOP commands from Imap.FolderSession (*)
  6871c1c... Make remote folder synchronisation a top-level API method (*)
  b717c32... Schedule folders for background sync even when open (*)
  8bb7d3a... Ensure folder is refreshed ASAP after creating a new messag (*)
  079d020... Handle Smtp.ClientService null condition better (*)
  4cc71e6... Handle headers having null date in ConversationMessage (*)
  d56508f... Clean up ImapEngine.CreateEmail replay op source code (*)
  dd24b22... Ensure new sent mail is found for services that auto-save (*)
  7b53137... Fix missing outbox messages body preview in ConversationVie (*)
  4ae0414... MinimalFolder::synchronise_remote: Handle sessions gone bad (*)
  02f1d89... Smtp.ClientService: Explcitly poll when waiting for sent ma (*)
  08c0573... App.ConversationMonitor: Don't force load ops to be local-o (*)
  81e566a... Merge branch 'wip/131-sent-mail' into 'mainline'

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