INT 15 U - DESQview/X - GET DISPLAY NAME                                        
	AX = DE29h
	BX = 0004h
	CX = size of buffer in bytes
	DX = segment of window handle
	ES:DI -> buffer for display name
Return: CF clear if successful
	    buffer filled with ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. display name (truncated if necessary) or
	      null string if no display
	CF set on error
Notes:	DESQview 2.50-2.52 are distributed as part of DESQview/X v1.0x.
	the name ":0" refers to the local display