cleaner fact freshening, which also works in corner cases, e.g. if two backquoted facts have the same name (but have different variable indices)
/***************************************************************************
Title: GraphBrowser/AWTFontMetrics.java
Author: Gerwin Klein, TU Muenchen
AbstractFontMetrics avoids dependency on java.awt.FontMetrics in
batch mode.
***************************************************************************/
package GraphBrowser;
public interface AbstractFontMetrics {
public int stringWidth(String str);
public int getAscent();
public int getDescent();
}