INT 21,17 - Rename a File Using FCB

	AH = 17h
	DS:DX = pointer to a modified FCB of the format:

	  Offset     Description
	    00	   drive designator
	    01	   original file name
	    09	   original file extension
	    11	   new file name
	    19	   new extension


	on return:
	AL = 00 if file renamed
	   = FF if file not renamed


	- allows renaming of files with normal attributes
	- "?" wildcard supported after DOS 2.1, "*" supported by
	  DOS 3.x+