Document strange behaviour of Inventory.addItem and use Java terminology for javadocs.
Merge #9

Thanks @cybertiger

commit 9f0eea7fbedfd989f4d90e0d8e7b1bbfb6ca8f11
Author: Antony Riley
Date:   2013-03-14 01:38:53 +0200

Document strange behaviour of Inventory.addItem and use Java terminology for javadocs.