2007/10/08 ver 1.5
	1. added r (range) option
2007/09/10 ver 1.4
	1. bug fix in ${...}$
	2. operation rank
2006/11/26 ver 1.3c
	1. bug fix in empty echo -n in code area
2006/11/19 ver 1.3b
	1. bug fix in empty $foo in text area
2006/09/05 ver.1.3a
	1. bug fix in multi-lines with tailing '\'
2006/08/23 ver.1.3
	1. sequence of dollars: the rule is simplified.
2005/04/16 ver.1.2b
	1. bug fix.
2005/02/02 ver.1.2a
	1. fix my URL in readme
	2. change Brdline() to Brdstr() in rit.c
2004/12/21 ver.1.2