Deprecate or adapt Masking?

[viking-sudo-rm]

Masking techniques were used in the old game to blend a continuous surface between bordering tile regions. This is probably no longer relevant, so it should be removed from the code base.

[viking-sudo-rm]

There is a lot of logic for masking in TileLayer.java.

[viking-sudo-rm]

Status: masking logic should be removed wherever possible. This will probably lead to big improvements in performance.

[viking-sudo-rm]

Remove Masking, but transfer some useful logic from this class into something else.

In particular, we need the logic for connectivity between grid nodes.