Click on canvas to deselect an item

A single click on the canvas should deselect an item.

In the screenshot below, I have selected "Register". Clicking on the canvas, should deselect it.

![screen shot 2014-09-18 at 1 42 16 pm](https://cloud.githubusercontent.com/assets/1521387/4319184/fd5b2584-3f28-11e4-991e-56c1c7e9954d.png)