code: function formatUsageHeader(headerContent) {
    var headerString =  headerContent instanceof Array ?
      headerContent.join(EOL) :
      headerContent;
  
    return headerString + EOL;
  }
docs: Formats and returns the user's header string or array.
  
  @param {Array|String} headerContent The usage header option string or array
  @returns {String} The formatted usage header string