ngCordova is obsolete

[jordanreedie]

ngCordova is obsolete and no longer being maintained.

(http://ngcordova.com redirects to the following issue)
ionic-team/ng-cordova#1452

For upgrading to ionic native:
https://github.com/ionic-team/ionic-native/tree/v2.x#angular-1

"Ionic Native works as a stand-in for ngCordova. In many cases, the usage is identical, but we import ionic.native instead of ngCordova as our module."

Looks like it should be relatively straightforward to upgrade, but we'll need to figure out in which cases the usage isn't identical. Fingers crossed the bluetooth stuff doesn't need to be changed....