* wip d2items system and item properties
* added loader for TreasureClassEx.txt
* wip item spawn from treasure class records
* wip items
* add call to init item equivalencies, remove treasure class test from d2app
* made item affix records global var a map of affix codes to the records
* changed how item to item common record equivalency is determined
* changed set items records export to a map of their codes to the records, grouped property params into a struct
* changed property parameter field from calcstring to string
* fixed bug in stat value clone
* adding equipper interface as part of stat context, eventually to be used to resolve set bonus (among other things)
* made the item interface simpler, only needs name and description methods
* adding equipper interface, for anything that will equip or have active items
* handle case where min and max are swapped, removed commented code
* added property/stat resolution for magic, rare, set, and unique items
* adding item generator which can roll for items using treasure class records
* fixed item equivalency func being called in the wrong spot