Make delwin() remove window from list of windows on its screen.
Free win->lspace and win->lines for subwins (they only share text space).
Free things in the correct (and same) order if malloc() fails in __makenew().
Adjust delscreen() for delwin() removing itself from winlist.
Fixes potential massive corruptions if delwin() called on a main window.
NB: not responsible for the sysinst core dumps :-(
do the translation ourselves (if the tty didn't do it for us).
Add debugging to track functions that change tty state.
Fixes PR 20834 by Stephen Borrill.
See the Single UNIX Specification, Version 2 :
http://www.opengroup.org/onlinepubs/007908799/xcurses/can_change_color.html
Also, add the functions :
use_default_colors();
assume_default_colors(fore, back);
(from ncurses) that allow the terminal default colours or user-specified
default colours to be used.