Factored TibetanDocument into two classes, one that is a

DefaultStyledDocument, and another consisting entirely of static utility
methods for processing Tibetan text.  Moved TibetanDocument.DuffData
into its own class.

I think this makes things a bit more transparent, and gets us a little closer to
making clean use of Swing.

source/org/thdl/tib/text/DuffData.java

@@ -0,0 +1,53 @@
+/*
+The contents of this file are subject to the THDL Open Community License
+Version 1.0 (the "License"); you may not use this file except in compliance
+with the License. You may obtain a copy of the License on the THDL web site 
+(http://www.thdl.org/).
+
+Software distributed under the License is distributed on an "AS IS" basis, 
+WITHOUT WARRANTY OF ANY KIND, either express or implied. See the 
+License for the specific terms governing rights and limitations under the 
+License. 
+
+The Initial Developer of this software is the Tibetan and Himalayan Digital
+Library (THDL). Portions created by the THDL are Copyright 2001 THDL.
+All Rights Reserved. 
+
+Contributor(s): ______________________________________.
+*/
+
+package org.thdl.tib.text;
+
+/**
+* A wrapper object for a stretch of TibetanMachineWeb data that shares the same font.
+* A piece of DuffData consists of a font number and a string.
+* The font number is a number from one to ten, corresponding
+* to the ten TibetanMachineWeb fonts, as follows:
+* <p>
+*    1 - TibetanMachineWeb<br>
+*    2 - TibetanMachineWeb1<br>
+*    ...<br>
+*    10 - TibetanMachineWeb9<br>
+* <p>
+* The string represents a contiguous stretch of data in that
+* font, i.e. a stretch of TibetanMachineWeb that doesn't require a font change.
+*/
+public class DuffData {
+/**
+* a string of text
+*/
+    public String text;
+/**
+* the font number for this text (see class description)
+*/
+    public int font;
+
+/**
+* @param s a string of TibetanMachineWeb text
+* @param i a TibetanMachineWeb font number
+*/
+    public DuffData(String s, int i) {
+        text = s;
+        font = i;
+    }
+}