Adds a new line after build error stack trace

Just a minor prettify in build stack error trace

**Before:**

![stack-before-new-line-termination](https://cloud.githubusercontent.com/assets/2162441/3988220/df6da2c2-28ad-11e4-852a-72dec0476445.jpg)


**After:**

![stack-after-new-line-termination](https://cloud.githubusercontent.com/assets/2162441/3988226/e55a095a-28ad-11e4-8a91-a4324dfa3614.jpg)



Can you use `require('os').EOL` instead of `\n` (so that it works properly on Windows)?