- added sanity checks to prevent a savegame from being loaded with an incompatible map
- refactored a few things to simplify serialization.
- started work on main level serializer function.
Now Scroll_Texture_Model is working properly again. (Note: Whoever designed this function must have been on drugs - its use of the source data in Boom is completely insane.)
While testing this it became clear that with the higher precision of doubles it has to be avoided at all costs to compare an actor's z position with a value retrieved from ZatPoint to check if it is standing on a floor. There can be some minor variations, depending on what was done with this value. Added isAbove, isBelow and isAtZ checking methods to AActor which properly deal with the problem.
