Disable the marsh biome by default.

... wait, disable by default?

For compatibility with old worlds, I can see this just fine.
For new worlds, with marshes working properly, shouldn't they be enabled like any other?

(I use EBXL in ages only, so they're disabled for me anyways.)

Disable by default because they have been bugged for a long time, don't work properly and don't even remotely resemble a marsh. We are removing it in v4, and will be adding a bog, however cannot do so in v3 as it would mess up people's world.

All these things are for v3...as everything will change completely for v4.

Updated biomesettings class in 73c5b0f to allow us to disable biomes by default if we have the need.

The marsh biome has been disabled by default as it is bugged.