[gtk] (15 commits) ...Merge branch 'fix-icontheme-invalidation' into 'master'

[Benjamin Otte <otte src gnome org>]

Summary of changes:

  e75bc28... icon-theme: Fix deadlock in GktIconTheme dispose (*)
  9861173... Stop using the -gtk-icon-theme style property (*)
  7aeef71... css: Get the icon theme via the settings (*)
  2ddff87... css: Drop the -gtk-icon-theme property (*)
  fe6ef52... icontheme: Keep a serial (*)
  58ca3b0... css: Compare icon theme serials (*)
  723d57e... widget: Add a system_setting_changed vfunc (*)
  129b8bb... window: Use gtk_system_setting_change (*)
  4b13d99... settings: Call gtk_system_setting_changed (*)
  a59cb5d... icontheme: Call gtk_system_setting_changed (*)
  679863a... image: Invalidate icon helper when icon theme changes (*)
  7b4378b... widget: Update when font settings change (*)
  a199060... Drop gtk_style_context_reset_widgets (*)
  94906d0... Drop gtk_widget_reset_style (*)
  8b1e857... Merge branch 'fix-icontheme-invalidation' into 'master'

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