[geary] (13 commits) ...Merge branch 'mjog/search-refinement' into 'mainline'

[Michael Gratton <mjog src gnome org>]

Summary of changes:

  c93cfc3... Clean up Engine search API (*)
  981ea84... Make Geary.EmailIdentifier serialisation a bit less ad-hoc (*)
  cb16bdc... Remove default Geary.EmailIdentifier::hash and ::equal_to i (*)
  b3488f6... Add Geary.Account::list_local_email_async (*)
  924104c... Clean up search folder implementation (*)
  130fd95... Remove Geary.Account::search_upgrade_monitor (*)
  f025f69... Move SearchFolder management into the client (*)
  5eb6bb2... Update and simplify SearchBar component (*)
  dda8d9b... Remove distinct search folder email identifiers (*)
  cc0fb9e... Remove unused Geary.Folder::list_local_email_fields_async m (*)
  77125fc... Remove some redundant collection copies (*)
  e7f8571... Move display-related Util.Email.shorten_url function to Uti (*)
  c9d6d96... Merge branch 'mjog/search-refinement' into 'mainline'

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