Fix #175: Add Ghost Collidable check (& some properties)

[unknownersamli]

didnt change too much, else I'm not sure something will go bad

I think if the Ghost can interacting with you, then it can change how the map working

[RedFlames]

To be clear, only the changes that set Collidable are actual changes, right? The rest is just refactoring?

My first question would be, if someone has interactions off, so Ghosts are spawned non-collidable, then they turn on interactions but have stayed on a screen with other players -- would they now still be unable to grab the players on screen until those respawn?

I imagine setting Collidable should maybe then be done every time Update() runs,
but then you'd still need to keep in mind the "cooldowns" that turn it off upon throwing someone, and such.

Actually, I see now that it does indeed get set in Update() in line 196. Hmm.

Should it be

Collidable = Holdable.Holder == null && holdable; 

instead of

Collidable = Holdable.Holder == null && MutualInteractable; 

to honor the cooldown? I imagine it should be the inverse of the first check in OnCarry that returns early, after all.

Though I am also inclined to say I don't like how the boolean there with the local variable is three levels of "nested" conditionals, by including Grabable which includes MutualInteractable...

If this would solve all the issues that arise from Ghosts being Actors though, that'd be cool.