Display a 'Modified' tag in the State column for modified pages

Completes #16

If a page has been 'modifed' (has unpublished changes) a 'MODIFIED' tag is displayed in the 'State' column. Similar to how it's displayed for a page in the Site Tree.

![](http://spdr.me/GlfZ+)
Could you also add this to the end of the timer state? Also if you could please add spacing in so it becomes 

`') . $modifiedLabel'`