Improve mobile navigation collapse

This is a small fix for an issue with Bootstrap's collapsing navigation on Meteor.

Before this PR, the navigation wouldn't collapse when going to a different route:

![http://recordit.co/nemaFR.gif](https://cloud.githubusercontent.com/assets/737065/2869351/c36ec41c-d267-11e3-818b-44c022f8f771.gif)

After this fix, clicking the link will also collapse the nav when clicking a `a` tag:

![http://recordit.co/eitvQe.gif](https://cloud.githubusercontent.com/assets/737065/2869352/d115d326-d267-11e3-9a08-00b2ac1a0b94.gif)