CB-6976 Add support for Windows Universal apps (Windows 8.1 and WP 8.1)

https://issues.apache.org/jira/browse/CB-6976

* Allow using new windows alias to work with old windows8 platform
* Allow using old windows8 alias to work with new windows universal apps
Do we really want to allow that? Sounds like it's better to warn here and ask to stop using the windows8 alias. If they already know about the unified platform and even added it, why would they use the windows8 alias? And if they do out of habit, why would we encourage that?