HUD Blinking

@kadst43 @ajiraffe Not merging this yet, since these are not hooked up. You can test them by calling the functions from the console and passing in the element identifier you want.

If someone else ends up hooking these up, my suggestion would be this:
- Fire an event from a trigger (`scene.blinkHUDElement` for instance)
- Pass the HUD element ID (i.e. `"blocklyButton"`)
- Catch the event in the view, via `vwf_view.firedEvent` and call the functions in this branch

That should be easy enough.