open external URL in internal default device's browser

Patch that allows to open external URLs in device's internal default browser. Also with JS-bindings.
Usage:
cc.Application.getInstance().openURL("externalURL");

Tested on:
Samsung Galaxy S4 Mini
Samsung Galaxy S4
Samsung Galaxy Note2
Google Nexus 10
Nexus One

Apple iPhone 5 with iOS7
Apple iPhone 4S with iOS7
Apple iPad Retina with iOS7