chore(): cleanup return values

Addresses https://github.com/driftyco/ionic-native/issues/38.

src/plugins/imagepicker.ts

@@ -50,12 +50,5 @@ export class ImagePicker {
   @Cordova({
     callbackOrder: 'reverse'
   })
-  static getPictures(options: ImagePickerOptions) {
-    // This Promise is replaced by one from the @Cordova decorator that wraps
-    // the plugin's callbacks. We provide a dummy one here so TypeScript
-    // knows that the correct return type is Promise, because there's no way
-    // for it to know the return type from a decorator.
-    // See https://github.com/Microsoft/TypeScript/issues/4881
-    return new Promise<any>((res, rej) => {});
-  };
+  static getPictures(options: ImagePickerOptions): Promise<any> { return }
 }