feature - filtering treema node.

I add a function which accepts a string as argument and it hides the nodes with title not matching to the string. At first I intend to add a filter to CodeCombat's Thang editor, but I find the component list is built by treema, so maybe it's better to add filter here.

This function is used in this way
<pre>
var treema = buildTreemaExample($('#demo'), product_schema, products);  
$('#filter').on('keyup', function(){
      treema.filterTreemaNodes($(this).val())
});
</pre>

Please have a look, any feedback would be appreciated.