Added java.util.Formatter implementation. Basic/common formats work,

such as %s, %d, %x... also width, left justify, zerofill flags are
implemented. Many of the other formats do not work, see the comments in
avian.FormatString javadoc and look for FIXME and TODO items for more
information on features that are known to not work correctly.

classpath/java/util/IllegalFormatException.java

@@ -0,0 +1,31 @@
+/* Copyright (c) 2008-2015, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+package java.util;
+
+public class IllegalFormatException extends IllegalArgumentException {
+
+  public IllegalFormatException() {
+      super();
+  }
+
+  public IllegalFormatException(String message, Throwable cause) {
+      super(message, cause);
+  }
+
+  public IllegalFormatException(String message) {
+      super(message);
+  }
+
+  public IllegalFormatException(Throwable cause) {
+      super(cause);
+  }
+
+}