fix window resizing

by just setting a flag in the signal handler, and checking it in
update_display(). We can not run update_display concurrently from the signal
handler.
add "mode" (AP, STA, IBSS, ...) filter
add command line option -f for packet filter
Edit help text and other text formatting
add new options to man page
clean up packet types

BATMAND and batman-adv are treated as one
combine RTS/CTS