Fix items in item frames being shot off. Fixes #725

Fixes the following cases:
* A player shoots an item out of the frame with an arrow
* A player tricks a skeleton into shooting an item of an item frame

Previously, the item would pop off in both cases, now it remains intact.
Merge pull request #759 from rutgerkok/itemFrames

Fix items in item frames being shot off. Fixes #725
Merge branch 'master' of https://github.com/phaed420/PreciousStones