Before gates on underground layer didn't had any channel assigned and of course any function that attempt to check -1 channel caused crash.
Also I find out that at point postInit executed It's possible to get mutable gamestate via gameState() callback so we don't need to pass it there.
Explore will also suggest AI to re-enter bidirectional teleporter in case of one of it's exits is not visible for some reason.
Also now AI won't try to visit teleporters in case if it's know that it's channel is impassable. E.g if map have several entrance monoliths of with same same SubID that don't have exit then AI will only try to visit one of them and later of he'll know that all other monoliths of this subtype is blocked because they all using same channel.
Now all new objects added to visitableObjs only using addVisitableObj so we can catch them for teleports handling.
I also simplified one of retreiveVisitableObjs functions because it's only used for inserting things into visitableObjs.
When AI going through bidirectional teleport it's always getting list of all available exits.
If some of exits are invisible it's will attempt to visit each of them teleport probing begins.
Each kind of teleporter have own function that determine if it's should or shouldn't be used.
For now Monolith with bidirectional channels and Subterranean Gate are united.
Transit is new option for hero movement. If it passed for movement then hero can get get on tile without visiting of object on it.
Currently it's will be only allowed is object under destination is teleport.
Just like TeleportDialog it's based off showBlockingDialog, but as number of package is higher when possible showTeleportDialog will be after other dialogs handling code.
TeleportDialog is based off BlockingDialog and it's needed for server to ask client what teleport hero should be teleported to.
It's also contain list of possible exits, identifier of currently used channel and also impassable option.
If impassable set to true then client will remember that current teleport channel is lack of exit point.
This code belongs to callback because both player and AI shouldn't directly access information about teleport channels.
For example pathfinder code need to check teleport channel type only based on information about objects player already seen.
