Return promise when using Angular
Breaking change! Returning the promise instead of the deferred should be preferred, as the promise is then()'able and this results in the same usage pattern as the jQuery case. Also, I don't think the deferred should be exposed. The Angular $q deferred is not then()'able, so you're required to use `cordova.getAppVersion().promise.then()`.
Merge pull request #22 from hartwig-at/angular-promise

Return promise when using Angular