code: public void setContentAddStyleNames(String value) {
          if (value == null || value.isEmpty()) return;
          JQMCommon.addStyleNames(content, value);
      }
docs: Additional class names can be added directly to content div for better custom styling.
  The same idea as UiBinder's embedded addStyleNames functionality.
  
  <br> Example:
  <pre>&lt;jqm:JQMPage contentAddStyleNames="aaa bbb ccc"/&gt;</pre>