Allow to ignore multiple objects when checking for collisions

[tobbi]

Basically, it's in the title.

Currently, only one object can be set as ignore object for the collision system. This is alright when we want to prevent self-collisions. However, sometimes multiple objects need to be ignored. For example in case of ledge behaviour where we want to prevent badguys from assuming players can be walked on.

Therefore, I changed GameObject* ignore_object to const std::vector<GameObject*>&.

Furthermore, I've changed the code to ignore players when checking whether the badguy may fall because we don't want badguys to consider players as suitable target for continuing to walk when their ledge behaviour is set to stay on the platform.

Fixes #3194

[MatusGuy]

Oops, accidentally reviewed sorry

[tobbi]

Why does this ignore only players now? Does this fix a bug?

Fixes #3194 (see title)

[tobbi]

Maybe RayCastIgnore::IGNORE_OBJECTS would yield the same result? IDK.

[MatusGuy]

I believe there's a better way of fixing this. For the BadGuy, you can detect if the object hit by the raycast is static, or, in other words, either COLGROUP_MOVING or COLGROUP_MOVING_STATIC.
If it's really needed to ignore objects (which is not the case in might_fall) we can think about this later. I'm rewriting these functions sooner anyway

[Hypernoot]

This actually fixes only the case when the bug is triggered by the player. But it can be triggered by any object in the group COLGROUP_MOVING. Problem is, that the group COLGROUP_MOVING sometimes acts as solid (the case of badguys) and sometimes acts as non-solid (the case of powerups and the player). Therefore, a badguy may still stand temporarily on COLGROUP_MOVING. Therefore, the correct behaviour would be:

• If the badguy stands on COLGROUP_STATIC or COLGROUP_MOVING_STATIC, then refuse to walk on COLGROUP_MOVING.
• If the badguy stands on COLGROUP_MOVING, then don't test for walkable ground. I guess that badguys are not supposed to walk on top of each other permanently.