Automatically re-select flying pawns (AbilityPawnFlyer)

[SokyranTheDragon]

In vanilla, whenever a pawn is flying/jumping they are automatically re-selected when they get despawned and their flyer gets spawned.

Those changes should bring this behaviour to all flyers using AbilityPawnFlyer. Changes made to achieve this:

• PawnFlyer_MakeFlyer_Patch was modified to (right after the flyer was constructed) check if it's AbilityPawnFlyer and the pawn was selected
  • If successful, it then check if the pawn should be selected by calling AbilityPawnFlyer.AutoSelectPawn (true by default), which other mods can change to configure their auto-selection behavior
  • It then sets the field AbilityPawnFlyer.selectOnSpawn to true
• During a call to AbilityPawnFlyer.SpawnSetup the value of selectOnSpawn will be checked
  • If it's true, the pawn (FlyingThing property) will be selected
  • If the pawn is null, it'll select the flyer itself as a fallback

Please note, some of the mods that are already using AbilityPawnFlyer may need to be recompiled. This is due to their base.SpawnSetup call potentially calling PawnFlyer.SpawnSetup instead of AbilityPawnFlyer.SpawnSetup. This affects Vanilla Factions Expanded - Pirates and potentially other mods.