'Tag' Mode Added

This completes Indy 500, and thusly Game 4. This one game took way longer than I'd have liked (it's not that I've been working slowly, just sporadically; not only do I have a bit of a procrastination problem, but life made sure to constantly interrupt me as well), but c'est la vie. I find it interesting just how quickly I've been able to implement these recent updates though. I guess it really is just a matter of actually working on things and getting stuff done (though I suppose not encountering any massive problems does help considerably).

I've also made a slight adjustment to collision btw.

I genuinely feel like I could yet spend so much more time on this game: polish it up further, add more tracks, maybe even more game modes, etc., and perhaps I'd eventually have something I'd feel comfortable charging a dollar for. Ultimately, however, I'd be better off continuing my learning endeavor. Hopefully Pac-Man doesn't take nearly as long.