Update TODO
Remove obsolete prototypes
Focus follows pointer needs enter notify events

It seems that pointer motion events are not sufficient to enforce
'focus_follows_pointer': some windows grab the pointer and catch those
events (e.g.: *zenity*), preventing *bspwm* from receiving them. So we
need to listen to enter notify events too.
New message: 'swap'
Cursor pointer feedbacks for 'grab_pointer'