Visual Studio warning

Show this on Windows when `apm install --check` fails after installing a package fails.

![screen shot 2014-07-02 at 3 43 28 pm](https://cloud.githubusercontent.com/assets/671378/3463509/bb062a74-023a-11e4-965b-7316d814ad5c.png)

This requires apm@0.70

Closes #146