Latest commit adding Floor item breaks code from upstream

[hoshi10]

Many changes which have been introduced with the addition of the Floor item conflict with upstream code. Some manual de-conflicting is necessary.

Also, bugs spotted with floor extension code.

[fabianschuiki]

Maybe the Floor item could behave in a way similar to Lobbies: It is not drawn behind existing items. But when an item is removed, it is replaced by a floor item of the same dimension. Adjacent floor items are collapsed into one. If an item is built ontop of a floor item, the floor item is split into the part on the left of the item and a part on the right of the item. This would remove the nasty sky color issues, although it is a bit more complex to implement.

Another approach would be to only draw the floor items when they are not covered by an item. This would require a map of what segments of a floor are covered and need not be drawn. I have the feeling though that this will boil down to the former approach being more feasible.

[hoshi10]

Thanks for your suggestions! Having 1 floor item per floor is a much simpler option and can double up as an easy check for maximum floor width on either end. I hope to continue in this direction unless it becomes more complicated than the alternatives you've mentioned.

Your 2nd point has reminded me of another possible approach I had though about earlier, but not in depth. Perhaps it is time to revisit it and see if it can be expanded upon.

[fabianschuiki]

Sounds good :) I won't touch too much of construction-related stuff in my branch then, so that we don't run into any more merging trouble.

[hoshi10]

Merging new floor code with upstream completed in commit 4f5111248d47e10d80677c956183799b9cad438b