Patch open url

This pull request should be merged to develop branch with tag cocos2d-x-2.2.1.
Detailed comparison you can see here: https://github.com/sortris/cocos2d-x/compare/cocos2d:cocos2d-x-2.2.1...patch-openURL

Patch that allows opening 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