Previously, papyrus was limited to the savanna biome.
Rainforest is a suitable habitat for papyrus.
Makes papyrus a little less difficult to find.
Move swamp jungletrees into a separate registration, to allow
applying distribution by perlin noise to keep these away from
papyrus areas.
Fix error: Remove non-functional 'rainforest swamp' from the
biome list for the jungle log decoration. It is not placed in
swamps due to the 'y max/min' and 'place on' parameters.
5b1875ef41