Core components relationship ===
Acquire other objects from a client
Class Property
tag c.tags
screen c.screen
awful.key c:keys()
awful.button c:buttons()
Acquire a client from other objects
Class Property
tag t:clients()
screen s.clients
screen s.hidden_clients
screen s.tiled_clients
mouse mouse.current_client
Legend: c: a client object, t: a tag object, s: a screen object, k: an awful.key object, b: a awful.button object, n: a naughty.notification object