[geary/wip/713150-conversations] (20 commits) ...Fix scrollbar detection & client-API loop for loading more when necessary

[Jim Nelson <jnelson src gnome org>]

Summary of changes:

  06e6b59... Don't allow border-radius in headerbars when using server-s (*)
  1d0e58b... Don't set conversation title for zero or multiple conversat (*)
  aa97d2c... Log total and reserved sessions in ClientSessionManager (*)
  e7900cd... Merge branch 'master' into wip/713150-conversations
  55ecbb6... Use separator within Gtk.Headerbar in MainToolbar (*)
  c67ca65... Fix edge case where FillWindowOps are continually reschedul
  bee2cfd... Disconnect from UI/Engine signals when closing app (*)
  5c8fffd... Merge branch 'master' into wip/713150-conversations
  c188f4d... Remove ConversationMonitor reseed operation
  a40fb75... Added Bosnian translation (*)
  b13dd76... Updated Kazakh translation (*)
  91492a0... Updated Polish translation (*)
  b8390ac... Updated Czech translation (*)
  b170be1... Add semicolon as trailing character for Desktop Entry Keywo (*)
  9bd509d... Updated Spanish translation (*)
  c5b2b5a... Remove subject and participants from headerbar (*)
  ddfa615... Updated Swedish translation (*)
  6a39622... Ensure archived/trashed messages removed after timeout: Bug (*)
  1024767... Merge branch 'master' into wip/713150-conversations
  9619493... Fix scrollbar detection & client-API loop for loading more 

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