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/electron/index.js

@@ -0,0 +1,10 @@
+var fs = require('fs')
+var path = require('path')
+
+var pathFile = path.join(__dirname, 'path.txt')
+
+if (fs.existsSync(pathFile)) {
+  module.exports = path.join(__dirname, fs.readFileSync(pathFile, 'utf-8'))
+} else {
+  throw new Error('Electron failed to install correctly, please delete node_modules/electron and try installing again')
+}