Update README.md
Adds blank unity project
Adds scene file and base terrain.

Don't consider the terrain functional.  You can delete it if it's in the
way.  Its just left over from messing around and I didn't get around to
rolling back all of the changes.
Floor, tiles, trees(kind of), and some other basics

-Adds a plane, flat on the Z axis, 1000x1000.
-Puts in an array to store the 50x50 grid of tiles.
-On start, randomly generates trees(Blue squares at the moment) all
around the center of the grid.
-Allows moving around the screen using arrow keys
-Some base code for getting what is on a tile based on your
mouseposition, and getting xy coordinates from the i,j in array.