Phrase object (with palindrome detector)

This is a sample NPM module created in [Learn Enough JavaScript to Be Dangerous] (https://www.learnenough.com/javascript-tutorial).

The module can be used as follows:

$ npm install --global michelbaas-palindrome
$ vim test.js
let Phrase = require("michelbaas-palindrome");
let napoleonsLament = new Phrase("Able was I, ere I saw Elba.");
console.log(napoleonsLament.palindrome());
$ node test.js
true