add onHeaderClick on column properties

README.md

@@ -295,6 +295,12 @@ React.render(<Table columns={columns} data={data} />, mountNode);
       <td></td>
       <td>Called when column's cell is clicked</td>
     </tr>
+    <tr>
+      <td>onHeaderClick</td>
+      <td>Function(event)</td>
+      <td></td>
+      <td>Called when column's header is clicked</td>
+    </tr>
   </tbody>
 </table>
 

src/Column.jsx

@@ -17,5 +17,6 @@ export default class Column extends Component {
     ]),
     render: PropTypes.func,
     onCellClick: PropTypes.func,
+    onHeaderClick: PropTypes.func,
   }
 }

src/Table.jsx

@@ -235,6 +235,9 @@ export default class Table extends React.Component {
       if ('rowSpan' in column) {
         cell.rowSpan = column.rowSpan;
       }
+      if (typeof column.onHeaderClick === 'function') {
+        cell.onClick = column.onHeaderClick;
+      }
       if (cell.colSpan !== 0) {
         rows[currentRow].push(cell);
       }