add ubuntu platform
CB-5188:
Added amazon-fireos platform.
1. User Agent detection now detects AmazonWebView.
2. Change to use amazon-fireos as the platform if user agent string contains 'cordova-amazon-fireos'
[ubuntu] specify policy_group
added ubuntu support
getPicture via web activities
fix camera for firefox os
[CB-5565] Updated version and RELEASENOTES.md for release 0.2.5