Copy ExtendedDFAdapter from bparser

ExtendedDFAdapter in bparser has been deprecated and then moved to an
internal test directory, so it can no longer be used by external
libraries like tla2bAST. As a temporary fix, this copies the deprecated
class into tla2bAST.

src/main/java/de/tla2b/output/ASTPrettyPrinter.java

@@ -5,8 +5,8 @@ import java.util.Hashtable;
 import java.util.Iterator;
 import java.util.List;
 
-import de.be4.classicalb.core.parser.analysis.ExtendedDFAdapter;
 import de.be4.classicalb.core.parser.node.*;
+import de.tla2b.util.ExtendedDFAdapter;
 
 public class ASTPrettyPrinter extends ExtendedDFAdapter {
 	private final StringBuilder sb = new StringBuilder();

src/test/java/de/tla2b/util/Ast2String.java

 package de.tla2b.util;
 
-import de.be4.classicalb.core.parser.analysis.ExtendedDFAdapter;
 import de.be4.classicalb.core.parser.node.Node;
 import de.be4.classicalb.core.parser.node.Start;
 import de.be4.classicalb.core.parser.node.Token;