Ores (non-mgv6 mapgens): New distributions

Make deeper, to compensate for ease of travel using 3D noise tunnels.
Make depth more progressive with value:

Ore, upper limit

Coal 64 no change
Iron 0 no change
Tin -32 > -64
Copper -16 > -128
Gold -64 > -256
Diamond -128 > -512
Mese crystal -64 > -512
Mese block -1024 no change

Make y of 1st density increase deeper but following a similar logic to before:

Ore, upper limit

Coal 0 no change
Iron -64 no change
Tin -128 no change
Copper -64 > -256
Gold -256 > -1024
Diamond -256 > -1024
Mese crystal -256 > -1024
Mese block -2048 new

Add second, denser layer of mese blocks with a decrease of separation and
increase in density equal to mese ore layers.