Implementation of Kinda Somewhat Elegant Digging (ready to pull)

Well, we've got to start somewhere. Digging is inside of this pull request, as well as the minor change that units owned get a small symbol over their head now to show that. I also ended up making a 'Beasts' folder, expecting that it is planned.

Looking forward to see how this all pans out.

While this digging implementation works when you have a single player, I expect it could become testy once you get quite a few players-- that will need to be looked into. I'll make issues for the specific issues which I can find once we have this merged. If we get it merged.

edit:
closes #7