Strip \r from output messages, if applicable

On Windows, the error panel will display (CR) symbols at each newline,
so remove them if they're present.

![capture](https://cloud.githubusercontent.com/assets/3087971/4384318/aee09e94-43b4-11e4-8aba-3576a010d123.PNG)

This is on Sublime Text 3 (x64, build 3064), on Win8.1 x64.