Add script that detects if cordova.js should be injected

This solves the issue of having cordova.js loaded when developing on the browser and having some features such as geolocation breaking. 
That code is based on the userAgent and we're using the platform. Do you know if the ones that are missing are the one's returned on the device from `navigator.platform`? @DanyHunter decided to use platform as the userAgent is spoofed in chrome and the platform is not