[Mode] Race to the randomly placed checkpoints

[alanrodriguezdotme]

Checkpoints are randomly placed in the map, and the fastest to get all of the checkpoints wins.

Options:

• Checkpoints are numbered, and players have to get them in numerical order to win.
• Randomly placed upgrades

[alanrodriguezdotme]

Finished:

• Checkpoints (coins, for now) are randomly placed around map, but only appear one at a time.
• Checkpoints change to semi-transparent after colliding with the car, next checkpoint becomes active.
• Added floating arrow to show where active checkpoint is.

Closing to create individual bugs for the next steps.