[gtk] (20 commits) ...Merge branch 'default-handling' into 'master'

[Matthias Clasen <matthiasc src gnome org>]

Summary of changes:

  1364eb2... window: Add a default-widget property (*)
  65052a5... Rename gtk_window_set_default (*)
  56e95dd... popover: Add a default-widget property (*)
  e464c08... window: Add a default.activate action (*)
  3ccdad7... popover: Add a default.activate action (*)
  f4880f5... Add gtk_widget_activate_default (*)
  7553d0c... label: Activate default via action (*)
  218d635... entry: Activate default via action (*)
  0ae71ca... mount operation: Handle default activation via action (*)
  3d1fdf7... file chooser: Stop using gtk_window_activate_default (*)
  0ae958d... Drop gtk_window_activate_default (*)
  89f7b97... Stop using gtk_widget_grab_default (*)
  fe3796e... widget-factory: Stop setting has-default in ui files (*)
  6d73443... widget: Remove special handling for has-default (*)
  59d50be... widget: Drop gtk_widget_grab_default (*)
  8880d27... inspector: Stop showing default widget in misc (*)
  92e21c3... Drop the can-default property (*)
  bf7d1e7... tests: Fix a default-related test (*)
  30942c4... Fix builder parser tests (*)
  6c472ed... Merge branch 'default-handling' into 'master'

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