Cleanup getModItem

[Nikolay-Sitnikov]

Cleans up the behavior of getModItem and the missing item fire.

Changes:

• GTModHandler.getModItem is no longer used, instead the new class IngredientFactory implements it.
• No more passing around missing into every call of getModItem
• createItemStack has been moved from IScriptLoader to IngredientFactory
• All usages of getModItem have been converted to static imports.
• getModItem no longer takes in longs, since ItemStacks can't go above int anyways.
• getModItem will create a custom fire item with a name that indicates the missing item when the dreamcraft.debug.recipe system property is set to true. The property is set by default in the development environment.

Also, getModItem is now much more optimized, with two less ItemStack copy operations per call and one less array allocation per call.