Terrain and Water

Added terrain and water. Plane starts running by default now. When
starting game, plane tends to do a front flip, gonna have to fix it so
it flies steady until we touch controls somehow. I have it at a decent
starting RPM initially, just need pitch to face up. I have it start at
45 degree angle up and landing gear retracts as if just took off. I did
this stuff b.c. our level has no place to land and also, so when others
start it all planes will be in air. We can add an airstrip if we wish.