Replace deprecated electron-prebuilt with electron@2.0.18

- Updated package.json to use electron@2.0.18 instead of electron-prebuilt@1.4.3
- Modified lib/jibo-cli.js to reference 'electron' instead of 'electron-prebuilt'
- This fixes compatibility issues with the simulator on modern Linux systems
- electron-prebuilt was deprecated and renamed to electron in 2016

node_modules/inherits/inherits.js

@@ -0,0 +1,9 @@
+try {
+  var util = require('util');
+  /* istanbul ignore next */
+  if (typeof util.inherits !== 'function') throw '';
+  module.exports = util.inherits;
+} catch (e) {
+  /* istanbul ignore next */
+  module.exports = require('./inherits_browser.js');
+}