[MC-57186] Can't load any world

I can't play at all. When I try to load any world or even create any world it crashes. At the top of the crash report it says:

Time: 18/06/14 18:51
Description: Exception ticking world

java.lang.NullPointerException: Exception ticking world
	at bfo.a(SourceFile:228)
	at bfo.d(SourceFile:158)
	at bab.a(SourceFile:548)
	at ot.a(SourceFile:262)
	at ou.a(SourceFile:198)
	at amg.a(SourceFile:111)
	at ou.c(SourceFile:159)
	at net.minecraft.server.MinecraftServer.w(SourceFile:570)
	at net.minecraft.server.MinecraftServer.v(SourceFile:506)
	at cof.v(SourceFile:132)
	at net.minecraft.server.MinecraftServer.run(SourceFile:422)
	at java.lang.Thread.run(Unknown Source)