Improve build failed emails

Created by: grit96

The build failed emails don't give much information currently. Perhaps we can show some command outputs or a link to GHL.

Imported comments:

By grit96 on 2015-06-23 11:31:22 UTC

We should probably make ghl responsible for sending emails

By grit96 on 2015-07-10 09:20:29 UTC

Not an issue