* Replace buckets to the selected hotbar slot, rather than the first available.
Replicates vanilla behaviour, as well as being more logical.
* Refactor cInventory::AddItem. Behaviour is now documented
* Add new cInventory::ReplaceOneEquippedItem and ::SetEquippedItem methods
* Return empty potion to the same slot after drinking
* Replace buckets correctly in other situations, not simply water and lava
Uses the new ReplaceOneEquippedItem method
* Correct collecting water from source block with bottle
* Add cPlayer::ReplaceOneEquippedItemTossRest method
* Handle stacked filled buckets (in theory)
Use new cPlayer::ReplaceOneEquippedItemTossRest method
