tv_kb_echo DEPRECATED

	old_echo_code = tv_kb_echo([echo_code.i2.r])

	This function will enable or disable keyboard echo for a TV window.
	Valid values of echo_code are KEY_ECHO_NONE, KEY_ECHO_ALL, 
	KEY_ECHO_NOTAB, KEY_ECHO_NOCTRL, and KEY_ECHO_NOKP. Only echo of 
	printing keys is affected. Cursor movement keys such as the arrow keys 
	are always enabled. Keyboard echo is enabled by INTYPE at 
	program initialization. When echo is disabled, the program may use 
	the TV_GET_KEY routine to find out about key presses.  The value of the 
	keyboard echo code before modification is returned in old_echo_code.

	This function requires the following include files:

	clib_h