Item stack limits should not be lowered on EE

[mike1072]

http://gibberlings3.net/forums/index.php?showtopic=28191&p=249038

EE has increased the stacking limit for some items, so when IR items (based on the BG2 stack limits) get installed, those stack limits revert back to the BG2 values.

Here are the BGEE values for all item types:

• Arrows, bolts, bullets, and darts: 80
• Throwing daggers, hammers, and axes: 40
• Potions: 24
• Gems: 20
• Scrolls: 50

We could either adjust all our stack sizes to match the Enhanced Editions or we could adjust our code so that it checks existing stack sizes and sets all our items to whatever the current size is, so IR's main component wouldn't be changing stack sizes in any games.