lib/browser/GraphBrowser/ParseError.java

added add_abbrevs(_i);
moved const_of_class/class_of_const to logic.ML;
added no_vars (from theory.ML);
added cert_def;
added const_expansion;
certify: refer to Consts.certify, which includes expansion;

package GraphBrowser;

class ParseError extends Exception {
	public ParseError(String s) { super(s); }
}