feat(plugin): add spinner dialog plugin

https://github.com/driftyco/ionic-native/issues/69

src/plugins/spinnerdialog.ts

@@ -0,0 +1,18 @@
+import {Plugin, Cordova} from './plugin';
+
+@Plugin({
+  plugin: 'cordova-plugin-spinner-dialog',
+  pluginRef: 'window.plugins.spinnerDialog',
+  platforms: ['Android','iOS','Windows Phone 8']
+})
+export class SpinnerDialog {
+
+  @Cordova()
+  static show(title : string, message : string) : Promise<any> {return}
+
+  @Cordova({
+    sync: true
+  })
+  static hide() : void {}
+
+}