CPRSTV(xbuf.sa.r, nchars.i2.r, cbuf.i1a.r, clen.i2.r, status.i2.r)

	This routine compresses TVMX format text into a compressed format
	for more efficient storage.  Savings of more than 50% are typical.  
	Even reasonably dense 48 by 120 images will fit into a 3930 byte 
	filesharing record.  Instead of storing a color code for each 
	character, only changes of color code are stored.  Blink codes are not 
	stored.  Repeated characters are stored as a repeat count and the 
	character code.  In order to limit the number of color codes stored, 
	the foreground color of blank characters may be changed to be the same 
	as that of the previous character. 

	text		user buffer of ASCII data and character attributes
	xbuf		buffer containing the text in TVMX format to be
			compressed (array of XCHAR structures)
	nchars		number of characters in 'xbuf' to compress
	cbuf		buffer to receive the compressed text
	clen		length of 'cbuf' in bytes
	status		conversion status
			(<0 -> not enough room in 'cbuf' to do the conversion,
			 >0 -> number of bytes used in 'cbuf')

	This function requires the following include files:

	cns_data_structs_h, clib_h

	Related functions:

	XPNDTV, window_tvsave_c, window_tvdisp(_c)