Relax FML source zip matching
Temporary fix for NPE on block-only ItemStacks, net.minecraft.item.ItemStack.func_77960_j(ItemStack.java:268)

https://gist.github.com/agaricusb/5608787
https://github.com/MinecraftForge/MinecraftForge/commit/b56d05ef9d6be5f3413cb62f2940f5b9cf3a8549