Environments Tropical Beach

This update includes:

- terrain grid seams fixed

- better and more accurate collision boxes around specific boxes and trees

- modified slope of beach into water so there's a shallow water "shelf" about ankle deep now to play in

- added 4 new CUA props to customize the scene in the form of 3 different tree stump sizes (I like the large one as it makes a decent natural chair or table to play on) and a stand alone palm tree.

- Changed foilage shaders to be more compatible with point lighting and nicer night scenes. Sadly they don't look as nice with directional based day light style scenes so I'm still looking for a unity shader that does both nicely, but this so far is a passable compromise.