Wingspan testbranch

[DuploMinh]

I made a more complete conversion to the the wingspan classification system. AClass class and type is introduced as well as value airplaneClass. Changed min airport size and slot allocation to match this.

[patsonluk]

@DuploMinh looking good! Sorry I kept forgetting to reply

Several minor points:

1. Might be better to use a more descriptive name other than AClass (I know Class is probably not available), it's more of my coding preference that I usually do not use short form unless it's very obvious. Can we use AirplaneClass or IcaoClass or WingspanClass etc?
2. I believe the current test case that verifies profitability should stay as is (using Type instead of AClass), as Type has bigger impact on fuel usage and capacity which are the determining factor of profit
3. I will change this PR to merge into a new v1.2 branch (not yet created) instead. Such that we can have a clean branch that contains all the v1.2 changes.

Thanks again for the hard work! I'm asking for more help with adding more airplanes for v1.2, btw where did u get the airplane data from? Im wondering if there's one good source that we can draw more standardized data, i was using wiki being but i dun think that's a good source. :)

[Edoebzd]

Hi @patsonluk I don't know if this can help, but i found two documents that contains airplanes data:

1. https://www.faa.gov/airports/engineering/aircraft_char_database/media/FAA-Aircraft-Char-Database-v2-201810.xlsx
   This is an excel file created by the FAA and it contains a lot of specific data for airplanes like wingspan, length, height, MTOW, parking area width, and many more.

2. http://www.dvbgroup.com/~/media/Files/D/dvbbank-corp/aviation/dvb-overview-of-commercial-aircraft-2018-2019.pdf
   This is a pdf containing more general data about airplanes. (It doesn't have as many airplanes as the faa one, but it has got all the main ones) It contains things like range, passenger capacity(also standard configuration with 2 or more classes), and more.

If you need some help with anything feel free to ask, and I'll try to help.

[DuploMinh]

I believe I have reverted the profitability back to using the Type instead of AClass which is now IcaoClass. Also, for sources on aircraft, I also used FAA fillings and databases. On the A350-900ULR, I had to do some guesswork based on the description given on articles and the Seat capacity used by Singapore Airlines.