chore(): cleanup return values

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

src/plugins/camera.ts

@@ -115,14 +115,7 @@ export class Camera {
   @Cordova({
     callbackOrder: 'reverse'
   })
-  static getPicture(options: CameraOptions){
-    // 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 getPicture(options: CameraOptions): Promise<any> { return }
 
   /**
    * Remove intermediate image files that are kept in temporary storage after calling camera.getPicture.