Improve exception details

Validation errors shown by 21551a838ed36f12a45892b4da273ddddfb40472 can be a bit hard to read, just adding new lines so it's easier to tell where 1 error starts and the other begins

This is what it looks like with this, instead of the array output

![Screen Shot 2013-02-22 at 11 21 28 AM](https://f.cloud.github.com/assets/139916/186227/1b14de5c-7d25-11e2-9d14-ae4c596edf1c.png)