: sqInt, bits the screen supports
To figureout how many bits the display surface is.
Must consider the hardware and window type and return the current depth.
This implies it's screen/device hardware based. However we really are dealing with what the window will support.
Gets the dominate screen hardware device and it's supported depth, if you have multiple screens this is the one with the menu bar.
This is a work in progress because we are still writting code to determine what depths the UIView logic will support
32 is returned, device does not support other depths
Returns depth of 1 if not connected to an X server, otherwise the XGetGeometry
depth based on current window, otherwise zero if error
if you have multiple screens, then something has to figure out what the main screen is.
Also since we are actually dealing with a window the window might have different colour depth than the screen.