Fixed Edge Case Bug

When Q=1 and SellIn=0 Normal Item would reduce quality to -1
Forced all Quality changes to use DecrementQuality.
New Feature: Implemented Conjured Item

Conjured item quality degrades 2x as fast as Normal item
Class is done; need to configure CreateFromItem still.
Updated CreateFromItem

Supports Conjured items now
Adjusted DecrementQuality

To ensure it can't make Quality negative given an amount > quality