decision for whether or not a pane should be drawn out of the layout code and
into the redraw code.
This is needed for the new layout design, getting it in now to make that easier
to work on.
maintain and is only going to get worse as more are used. So instead, add a new
uint64_t member to cmd_entry which is a bitmask of upper and lowercase options
accepted by the command.
This means new single character options can be used without the need to add it
explicitly to the list.
terminal to be switched between several different windows and programs
displayed on one terminal be detached from one terminal and moved to another.
ok deraadt pirofti
