title: Access MVEL ASTNode info
body: <p>After compiling an MVEL expression, I can access the top ASTNode.</p>
  <pre><code>ExpressionCompiler compiler = new ExpressionCompiler(&lt;expression&gt;, true);
  ASTNode node = compiler.compile().getFirstNode();
  </code></pre>
  <p>However, I would like to have full access to the ASTNode info, including its left and right child nodes.</p>
  <pre><code>ASTNode left = node.getLeftNode();
  ASTNode right = node.getRightNode();
  ...
  </code></pre>
  <p>Is there a way to do it?</p>