---------------------------- SCREENS -----------------------------

These values show you the data of the screen that the current gui
is (or will) open on. 

While the current gui is usually the active one this can be changed 
with the info command. So, you can see any public screen's data by 
say, making a dummy gui and setscreening it to the screen you
want (don't open it), and then choosing it with the info command. 

SCREEN.W        screen width
SCREEN.H        screen height
SCREEN.BAR      screen's title bar height
SCREEN.NAME     screen's name
SCREEN.DEPTH    number of bitplanes of screen's bitmap
SCREEN.COLORS   number of colors screen can show