title: How do you clear attributes from NSMutableAttributedString?
body: <p>How do you set all the attributes in an <code>NSMutableAttributedString</code> to nothing? Do you have to enumerate through them and remove them?</p>
  
  <p>I don't want to create a new one. I am working on the <code>textStorage</code> in <code>NSTextView</code>. Setting a new string resets the cursor position in <code>NSTextView</code> and fires the delegate.</p>