Upgrated ship movement to feel more natural

- wheels straighten out themselves
- limited the max speed of the ship
- ship now automatically brakes when going into a corner, so turns slow
down the ship ship significantly
- made the wheelbase longer (slower turns, the steerable wheels closer
to where the ship's rudder would be)
- wheels don't fall through the floor so easily
- camera position changed slightly
Merge pull request #3 from okacat/master

Upgrated ship movement to feel more natural