Add Windows Phone (universal) compatibility

[andreszs]

The old WP8 platform has been deprecated, could you update the plugin to add Windows Universal (APPX) support? This platform is for both Windows Phone 8.1 and Windows 10 phones.

Also, at the cordova plugins site, you forgot to add the WP8 compatibility icon, currently only the Android and iOS icons appear.

[abforman]

See: https://msdn.microsoft.com/en-us/library/windows/apps/jj651676.aspx

just use the progress tag with a class="win-ring"