code: function getCurrentBranch(verbose) {
    return Promise.resolve()
      .then(execCmd.bind(null,
        'git',
        ['symbolic-ref', 'HEAD', '-q'],
        'problem getting current branch',
        verbose
      ))
      .catch(function() {
        return '';
      })
      .then(function(result) {
        return result.replace(new RegExp('^refs\/heads\/'), '');
      });
  }
docs: Returns name of current branch or empty string if detached HEAD
  @return {string} - name of current branch