Oceans

I've now added simple ocean rendering to AeroCEO.

It's a simple blue sphere, created by geodesic tessellation so the triangles are equally spaced. As latitude and longitude will bunch up towards the poles.

I did a bit of play with the depth buffer again, to avoid z fighting where the water is very close to the land. The ocean is pushed back so the land has priority.

I've also turned on back face culling so the back side of the world is no longer rendered, since it can't be seen now with the water in the way.