This commit handles everything except actually respawning
the player at a checkpoint.
- Checkpoints are formed by two checkpoint things (2030):
- thingarg0 - The ID for the checkpoint. Must be the
same for these two things, and these two
things only. ID cannot be 0.
- angle - The direction the player is intended to face
after respawning. Must be the same for both
things.
- Each checkpoint thing is a starpost with a stick and an
orb at the end.
- By default, the sticks are lowered to horizontal and
face toward the opposite starpost.
- Rainbow tether sparkles form a field between the two
starposts.
- When a player crosses between these two starposts, each
spins in the direction that the player crossed. The
sparkles also fly out in that direction.
- Over time the sticks pivot upward.
- When the starposts are done spinning, the sticks will be
pointing straight upward.
- Orb at the end of the stick begins flashing when the
starpost is done spinnning.
- Players may cross multiple checkpoints.
- When this happens, any previously activated checkpoint
will have its stick lowered back to horizontal, and its
orb will stop flashing.
