Fix the rotation of airplanes

[jdno]

When airplanes reached the end of their flight plan, some random nodes were added to the plan to keep the airplane moving. When that happened, however, the rotation of the airplane's sprite was not updated. This resulted in airplanes moving sideways for a step in their flight plan, before being rotated correctly during the next step.

To fix this, a new system has been introduced that checks the rotation of each airplane on every frame. This can be optimized in the future to occur only when the flight plan of an airplane is updated.

[codecov-commenter]

Codecov Report

Merging #129 (2de460f) into main (a32e0c8) will decrease coverage by 0.24%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main     #129      +/-   ##
==========================================
- Coverage   56.70%   56.45%   -0.25%     
==========================================
  Files          46       47       +1     
  Lines        1388     1394       +6     
==========================================
  Hits          787      787              
- Misses        601      607       +6     

Impacted Files	Coverage Δ
game/src/scene/game.rs	0.00% <ø> (ø)
game/src/systems/follow_flight_plan.rs	73.33% <ø> (+4.58%)	⬆️
game/src/systems/rotate_airplane.rs	0.00% <0.00%> (ø)
game/src/systems/spawn_airplane.rs	0.00% <0.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a32e0c8...2de460f. Read the comment docs.