Towers!

There is  still a lot to be done with ironing out the way the code is set up, but towers are a thing now.

What you are looking at is a bear walking towards a knight sitting in a tower.  What will happen here is that the bear will pound away at the tower while the knight attacks the bear.  The knight attacks as normal, but doesn't move.

I need to redo movement and the cursor, but with this kind of architecture, I think I could do really neat things.  Like, you could theoretically mount any unit on top of any other unit, and the "top" unit would do the attacking while the "bottom" unit did the defending.  I need to think about how I want this to work.