message: Print YAML errors using Display
  Much nicer error message than with Debug.
diff: @@ -997,7 +997,7 @@ impl ::std::fmt::Display for Error {
  write!(f, "could not read $HOME environment variable: {}", err)
  },
  Error::Io(ref err) => write!(f, "error reading config file: {}", err),
  - Error::Yaml(ref err) => write!(f, "problem with config: {:?}", err),
  + Error::Yaml(ref err) => write!(f, "problem with config: {}", err),
  }
  }
  }
  