Tree Wall and Cleanup Update

This is a pretty big update that makes some significant improvements to the corner/angle tiles on the single-level water's edge. I also made improvements to the grass and shallow water textures and tweaked the colors a bit. If you don't like these changes, I'm leaving the previous version available for download. In addition, I've also added a full custom tree wall autotile! These supertiles are 128x128, and allow you to easily build the outer walls of your forest maps. Easy peasy!