Support automatic refresh when running as a mobile app

[mirkonasato]

Similar to ionic run/emulate --livereload.

[mirkonasato]

Manual steps working with the Android emulator (for my own reference - will automate/simplify later).

In webpack.config.js add to the devServer section:

• host: '0.0.0.0' to make the server accessible
• contentBase: path.resolve('cordova/platforms/android/platform_www') to serve cordova.js

In package.json:

• "serve:cordova": "webpack-dev-server -d --env.BUILD_TARGET=cordova"

In cordova/config.xml:

• <content src="http://10.0.2.2:8080/" /> rather than index.html

Start the dev server with npm run serve:cordova and deploy the app with cordova run android --emulator.