Add collision_mask to find_entities_filtered

[Boodals]

I was surprised to find that find_entities_filtered doesn't have a filter for collision_mask. It seems like the perfect use for the function.

It should be a string or array of strings, similar to the name and type filters. It would find any entity that collides with any of the entries in the provided collision mask.
find_tiles_filtered already has a collision_mask filter, but it is only one string. Changing it to also allow an array of strings would be useful, for example to find tiles that would collide with an entity.

[Bilka]

I have added collision mask string/array of string for both entity and tiles search for 0.17.