Add:

meta_display_rebuild_keybindings
meta_display_add_xlet_keybinding
meta_display_remove_xlet_keybinding

to allow runtime keybinding assignments without gsettings involvement
Add gi method to allow invoking keybinding handler during a global clutter
event grab (menu or other clutter actor has focus)
Added meta_display_get_is_overlay_key for the menu applet
Change 'xlet' naming to 'custom'
Merge pull request #74 from mtwebster/keybindings

Add extra functions for allowing bindable hotkeys from applets, desklets, extensions.