AIPlus feature - sailor needs to hold the flag where a serf is dropped off

[tlongstretch]

I have a stub but this is not implemented yet. When dropping a serf off, the serf doesn't actually become active on the map until the sailor is one tile away from the flag (because they cannot both occupy the same pos). The flag needs to be "held" for that serf so other serfs cannot entire the flag tile, or an exception will be thrown.

[tlongstretch]

There's a few ways to handle this. The approach I am trying now is to create a new Flag bool 'boat_passenger_being_dropped' and have any serf about to enter that tile wait if that flag is true. However, I am realizing this forces me to add code for every single serf state.

Other ways:

• have the sailor not actually move to the flag in terms of game/map, but animate it as if he did. Put the passenger at the flag
• have the sailor not actually move away from the flag in terms of game/map, but animate it as if he did. Replace the sailor with the passenger at the flag once the sailor reaches 1 tile away
• somehow have two serfs at same pos
• hack the 'has_serf' check that is used to determine if a tile is occupied and make it return true for a passenger dropoff. This is the simplest way but I think it would introduce issues

[tlongstretch]

ahhh... I didn't need any of that stuff at all. I am now having the sailor's position immediately taken by the dropped off passenger serf rather than doing the one-tile-away method. This looks much smoother too as the dropped serf starts working immediately instead of being frozen at the flag until the sailor reaches one tile away.

[tlongstretch]

need to remove that "hold flag" code, test it a bit more, then this can be closed

[tlongstretch]

works great