title: jqgrid editoptions: required not functioning
body: <p>ok not sure what i'm doing wrong here:</p>
  
  <pre><code>            $("#list").jqGrid({
              url: --URL--,
              datatype: 'json',
              mtype: 'GET',
              colModel: [
                { label: 'Index', index: 'Index', key: true, hidden: true },
                { label: 'SampleSize', index: 'SampleSize', editable: true, editrules: { required: true, number: true} },
              ],
              pager: '#pager',
              rowNum: 10,
              rowList: [10, 20, 30],
              viewrecords: true,
              height: 'auto',
              width: 'auto',
              editurl: '.',
              createurl: '.',
              deleteurl: '.'
          });
  
          $('#list').jqGrid('navGrid', '#pager',
              { edit: true, add: true, del: true, search: false },
              { url: '#' }, // edit options
              {url: '#' }, // add options
              {url: '#' }, // delete options
              {}, // search options
              {}
          );
  </code></pre>
  
  <p>when editing / creating a record, i can keep the textbox for 'samplesize' empty and jqgrid does not throw any kind of error. am i forgetting to add something in?</p>