Wraps the internal inventory into an ItemListIgnoreCrafting to hide
craftable items from it. As the ItemLists will always create a copy of the
actual stack before changing them, it will not affect any itemstack stored
elsewhere.
Reduces the visibility of all fields to private and create setters/getters
when necessary. Exceptions are fields with GuiSync as these need to be
public.
Reduces the visibility of internal methods to private/protected/default when possible.
yueh