[14w18a] Crash shortly after joining server related to item frames

Put the summary of the bug you're having here

What I expected to happen was...:
World loads up as normal, like 14w17a

What actually happened was...:
The world loads up for a few seconds and then crashes back to the launcher

Steps to Reproduce:
1. Load a world running from a server on 14w18a
2. Have item frames in the world (Possibly maps in the frames could have caused this)
3. Game crashed and reports a NullPointerException about rendering entities - Item Frames