Forge CraftingHelper improvements

I have a few suggestion to improve the quality of the "CraftingHelper" class:

- "register" should be private, as it doesn't work for custom registrations even if you want.

- what about adding some extra custom conditions? E.g.

public class ForgeHasOreConditionFactory implements IConditionFactory {
    @Override
    public BooleanSupplier parse(JsonContext context, JsonObject json) {
        String ore = JsonUtils.getString(json, "ore");
        return () -> OreDictionary.doesOreNameExist(ore);
    }
}

- would somebody be interested if I write a section on 1.12 recipes to add https://mcforge.readthedocs.io/en/latest/ ?