Oregen and a few recipe tweaks

* Change harvestcraft pot to "copper pot", for the lulz.
* Remove fertilizer recipes in minetweaker, as metallurgy has them now.
* Add metallurgy fertilizer to oredict.
* Configure salt oregen using cofh worldgen, instead of harvestcraft's
* Disable water -> salt recipe in harvestcraft, instead of minetweaker.
* Oregen tweaks:
	* Osmium veins are a little smaller
	* Copper, platinum, and manganese are slightly more common
	* Zinc spawns more often, higher in the world, but in smaller veins
	* Silver and lead veins are less common.