Cordova Plugins with Vue + Framework7

Barcode scanner integration

**Problem:** can’t access barcode scanner plugin methods from Vue

If we can’t figure out how to surmount, may need to abandon Vue altogether & go w/ another approach

Reproduce:
1. Good starter (framework7): https://blog.toast38coza.me/building-a-mobile-app-with-vuejs-cordova-webpack-and-framework-7/
2. Barcode scanner Cordova plugin (install w/ cordova command): https://www.npmjs.com/package/cordova-plugin-barcodescanner
3. Attempt to invoke this method:

```js
cordova.plugins.barcodeScanner.scan(
      function (result) {
          alert("We got a barcode\n" +
                "Result: " + result.text + "\n" +
                "Format: " + result.format + "\n" +
                "Cancelled: " + result.cancelled);
      },
      function (error) {
          alert("Scanning failed: " + error);
      }
   );
```

## Issues/Posts:
* https://github.com/AppointmentGuru/webpack-mobile-f7/issues/4
* https://forum.vuejs.org/t/how-to-import-barcodescanner-in-vuejs-component/17608/6
* https://github.com/kartsims/vue-cordova/issues/11
* http://forum.quasar-framework.org/topic/599/cordova-cordova-plugin-qrscanner-plugin-preview-not-showing

## Side-Issue: vue-cordova

(Note: There may be a way to sidestep Vue-Cordova altogether)

Vue-Cordova: http://kartsims.github.io/vue-cordova/vue-cordova/

Vue-cordova exposes a cordova obj (ex Vue.cordova.blahblah) & plugins on global “Vue” but from source it looks like user needs to manually add support plugins (unsuccessful so far):
* https://github.com/kartsims/vue-cordova/issues/11
* https://stackoverflow.com/questions/43629684/add-cordova-plugins-to-vue-cordova
*

Idea alluded to by author in closed issue #11 (couldn’t get to work, should be “mounted” of component?)

```js
Vue.cordova.on('deviceready', function () {
  cordova.plugins.barcodeScanner...
})
```