Camera should expose Camera Constants

[andrewmcgivery]

I should be able to do something like this using Camera.DestinationType.DATA_URL but Camera from ionic-native does not expose CameraConstants from the plugin.

import {Camera} from 'ionic-native';

Camera.getPicture({
  destinationType: Camera.DestinationType.DATA_URL,
}).then((imageData) => {
  this.base64Image = "data:image/jpeg;base64," + imageData;
}, (err) => {
  console.log(err);
});

From the plugin:
https://github.com/apache/cordova-plugin-camera/blob/master/www/CameraConstants.js