message: fix autocomplete on linux
  On linux autocompletion doesn't work and `npm test` fail on autocompletion because of
  `/bin/sh: 1: printf: %q: invalid directive`
  Setting child_process default shell to /bin/bash fix autocompletion and tests.
  I don't know if it causes any issues on osx, but on linux it works like a charm.
diff: @@ -65,6 +65,7 @@ export function executeCommand(
  ...execOptions,
  env: _.extend({PWD: directory}, process.env),
  cwd: directory,
  + shell: "/bin/bash",
  };
  ChildProcess.exec(`${command} ${args.join(" ")}`, options, (error, output) => {
  