Merge pull request #325 from dalkon/master

Fix Item:setAttribute
Reduced memory footprint & optimizations

Reduced memory footprint of Creature (moved manaMax to Player and
removed checkCreatureVectorIndex)
Removed redundant cast in FileLoader
Optimized checkCreatures code (removed unnecessary code and using
swap/pop_back for O(1) removal in vector)
We'll now also have perfectly balanced buckets instead of relying on
randomness for that
Fix memory leak
Code cleanup/optimizations
Fix bug with ammo slot