Fix a rotation bug, and implement camera controls

Pressing L will center the camera behind the captain. L+R will cycle
between follow distances. R still adjusts the height.
Dial back FOV to a more sane 45deg

Also moved it into project settings
Make it green! And checkered! (ground plane)
Fix ground plane sizing, and implement better color

Ground plane is now actually the width you specify, instead of being
entirely wrong. Checker color now uses color/2, as opposed to a funky
mask; this is more correct and more tolerant of weird hues.