Crash if waila is not installed

[feldim2425]

Just to let you know that I have already found this bug.

I will fix it in the next version.

Crash Report:
cpw.mods.fml.common.LoaderException: java.lang.NoClassDefFoundError: mcp/mobius/waila/api/IWailaEntityProvider at cpw.mods.fml.common.LoadController.transition(LoadController.java:163) at cpw.mods.fml.common.Loader.initializeMods(Loader.java:739) at cpw.mods.fml.client.FMLClientHandler.finishMinecraftLoading(FMLClientHandler.java:311) at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:552) at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:878) at net.minecraft.client.main.Main.main(SourceFile:148) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)