Fixed missing terminal newlines when calling '--help'

This pull request fixes a missing terminal newline after printing documentation via '--help'.

Before:
![screenshot from 2014-07-26 06 17 08](https://cloud.githubusercontent.com/assets/835618/3710446/5e39adb6-148c-11e4-8188-1d5b9f305df0.png)

I couldn't run your unit tests (I'm on an unstable version of roxygen), but travis-CI should test this pull request upon submission.