item dropping now works like useItem and attack. we capture the button event locally in PlayerInventorySystem and send a server request via DropItemRequest which is handled in the CharacterSystem. Dropped items now show up on the server.
dropped items are no longer duplicated locally
item is now correctly destroyed on drop in the server
Merge branch 'multiplayer' into multi-dropItem

Conflicts:
	src/main/java/org/terasology/logic/characters/CharacterSystem.java
got rid of my NetworkEvents, using AbstractEvent instead.
got rid of runLocally on @Server annotation. onDropItemRequest now simply ignores the event client-side
on dropping an item, stack reduction and item removal is now performed using the inventory manager
fixed the removeItem() call in CoreInventoryManager. Fixed the style on my if statements
there is now an overload of setStackSize in inventory managerthat will destroy the item when newStackSize is set to 0. There is now less inventory logic in dropItemRequest in the character system
Merge pull request #484 from sdab/multi-dropItem

Item dropping now correctly multiplayer enabled, with dropped blocks working correctly.