The big fat Metallurgy/Nether Ore balance pass

This has been a loooooong time coming. :)

Ore frequency in general has been reduced in the Overworld
Iron, Redstone, Manganese and Emerald in particular have had their frequency slashed
Utility ore spawns have been slashed immensely
Bitumen is completely disabled and does not spawn
Nether oregen has been totally redesigned to make the Nether a more attractive mining destination - on average you will get a 300%+ yield compared to the Overworld once processed
Atlarus and Adamantine have been moved to the Twilight Forest and massively reduced in frequency
Mithril and Orichalcum have been made much more prominent finds in TF
Fantasy alloying metals have had their spawn range narrowed to make tham realistic to find
Gold has been moved down in the Overworld/TF to compensate for the void moving Atlarus and Admantine left
Platinum has been exiled to the mountains and is as rare to find as was originally intended!