Expose the underlying undomanager to fit Arduino IDE needs

Author: facchinm

gradle.properties

@@ -1,3 +1,3 @@
 # Note that Maven- and signing-related properties are in <maven-home>/gradle.properties
 javaVersion=1.6
-version=2.6.1
+version=2.6.1.1+arduino

src/main/java/org/fife/ui/rtextarea/RTextArea.java

@@ -1675,6 +1675,13 @@ private void writeObject(ObjectOutputStream s) throws IOException {
 
 	}
 
+	public RUndoManager getUndoManager() {
+		return undoManager;
+	}
+
+	public void setUndoManager(RUndoManager undoManager) {
+		this.undoManager = undoManager;
+	}
 
 	/**
 	 * Modified from <code>MutableCaretEvent</code> in