INT 50 - PCIBM PC Thuis Organizer Shell - DO LINE
	AX = 0007h
	ES:BX -> text string
	CX = string length in bytes (0000h if NUL-terminated)
	DL = FFh to center string, else flush left
	DH = upper left row
	DI = window handle
Return: AX = status
	    0000h successful
	    FFFFh error
Program: The PCIBM PC Thuis Organizer Shell was written by John Vanderaart and
	  published in the June/July 1990 issue of PCIBM PC Thuis Power magazine
SeeAlso: AX=0008h