leading / path fix for IE, revert changes to go()

I also added a 'data-iron-router-ignore' attribute for a-Elements. This is a bit hacky i admit. The reason is, if you have an a-tag for a twitter bootstrap-modal you put the id of the modal to the href of the a-tag with an #.

So if you can make the a-tag for a twitter bootstrap modal like this:
<a data-toggle="modal" href="#createSiteModal" data-iron-router-ignore="true">...</a>

The iron router ignores the event then. It works for me as a workaround until they figured something out. But it does not break anything too.