v17-pre3

I've been hard at work over the past few weeks. I rewrote all of the airplane code internally, and changed how the game handles them. You will no longer deploy plane models; instead, you will now have to pick from actual planes that exist in your hangar.

I consider preview updates, especially earlier ones like this one, to be broad brush strokes that I use to try and set the tone for the game. That means that a lot of features may be bugged or not fully fleshed out, so I welcome any feedback on what I can do to fully realize the potential of this update. As always, I am humbled to interact with the small yet passionate community that has formed around this game and it keeps me motivated to continue improving this game.

Note that I will be gone next week so you may not get a pre4 until mid-late March. Thank you for your patience and I hope that this week's preview update is smooth enough to play and has enough content to tide y'all over until then.

Features:
- Fleet Capacity has been replaced with a new Service Points mechanic.
- You will naturally gain service points over time, and this can be accelerated by unlocking more airports and building maintenance hangars.
- Planes will consume service points to repair themselves after flights.
- Planes will now lose health during flight, especially during takeoff and landing.
- Low health will greatly increase crash risk.
- Busy planes may have trouble maintaining themselves. You can change the maintenance strategy of a plane.
- Planes now have an age. Older planes will lose health faster, a.k.a. have more expensive upkeep.
- Airport gate view now shows passenger demographics
- Manufacturers now have agency
- You will usually see them saving up money but sometimes they might go and open a new production line.
- They will research new plane models if there are any for them to research.

Changes:
- Levering remembered how to build the Roebling. Midvale found the blueprints for the PAX-700 collecting dust in some former intern's filing cabinet.
- Tripled the build time of planes.
- Renamed 'Premium' to 'Business' and 'Lie Flat' to 'First Class' to be more intuitive.
- When a production line has orders in both the priority list and waitlist, we now allocate 70% of the work towards the priority list and the remainder to the waitlist.
- Streamlined navbar
- Can now view your hangar again, via the renamed "Network & Hangar overview"
- Can retrofit older blocks into the newest block by spending miles and service points
- Improved Airplane GUI (and renamed it)
- Redone location, daily profit and turnaround time badges.
- Now pick from existing planes rather than model+block combinations; can purchase used planes if desired.
- Total rewrite of how aircraft work in the code.
- Aircraft size has been streamlined to 'Small' and 'Large'.

Bugfixes:
- Fixed really annoying minor bug where manufacturer GUI would not highlight the current manufacturer on re-open.
- Fixed an ancient bug with repositioning where planes did not take into account planes already flying to the next destination.
- Fixed a bug with repositioning where planes would try to get a takeoff slot from the first airport of their route, regardless of whether they are repositioning from there or not.
Breaking Changes:
- Due to renaming 'Premium' to 'Business' and 'LieFlat' to 'FirstClass', custom seating templates have broken. Please delete and re-create them.