Add tooltips to actions.
Fix potential crash on mouse motion.
Add scroll accelerators.
Speed up smooth scrolling.
Remove todo note about accelerators.
Added a progressbar to the statusbar.
Reorder Booru::Image creation in get_posts.
Change startup code again, changed thumbbar/booru_browser actions.
ui node is not needed in get_action.
statusbar: Use set_size_request instead of setting progressbar widget style.
imagelist: Change index setting.
booru/tagentry: Limit completions to 15, remove unused timeout.
config: Sort config hash before saving.

Also added SiteList class.