[gtk] (12 commits) ...Merge branch 'mainloop-cleanup' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  9eeeb63... win32 printing: Stop using gtk_events_pending (*)
  24917ac... tests: Stop using gtk_events_pending (*)
  ebc720b... Drop gtk_events_pending (*)
  49a6ad3... Drop gtk_main_iteration (*)
  7eb889c... Drop gtk_main_level (*)
  c789711... Stop using gtk_main_quit (*)
  a6c5466... Stop using gtk_main and gtk_main_quit (*)
  4c22939... docs: Update an example (*)
  4dd780a... Drop gtk_main and gtk_main_quit (*)
  a8db322... Drop gtk_get_main_thread (*)
  eec219e... docs: Mention gtk_main in the migration guide (*)
  59b935a... Merge branch 'mainloop-cleanup' into 'master'

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