fix TryPlaceOnLand's ambiguity/messup wrt to making terrain indestructible (had boolean parameter for indestructible AND landflags parameters that could contain lfIndestructibly)
07f3bf8d98a3
Hedgewars.png had a resolution more than twice as high as required; also fixed some (mostly obsolete) code that also contained a typo that would cause a warning/note in clang
