[Crash] Missing minetweaker. Maybe turning Minetweaker an optional dependency?

[Desempregago]

[Client thread/ERROR]: Caught exception from Meltery (meltery)
java.lang.NoClassDefFoundError: minetweaker/IUndoableAction
at meltery.Meltery.init(Meltery.java:41) ~[Meltery.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_111]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_111]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_111]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_111]
at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:641) ~[forge-1.11.2-13.20.0.2309-universal.jar:?]
at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_111]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_111]
at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74) ~[guava-17.0.jar:?]
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47) ~[guava-17.0.jar:?]
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322) ~[guava-17.0.jar:?]
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304) ~[guava-17.0.jar:?]
at com.google.common.eventbus.EventBus.post(EventBus.java:275) ~[guava-17.0.jar:?]
at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:252) ~[forge-1.11.2-13.20.0.2309-universal.jar:?]
at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:230) ~[forge-1.11.2-13.20.0.2309-universal.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_111]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_111]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_111]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_111]
at com.google.common.eventbus.EventSubscriber.handleEvent(EventSubscriber.java:74) ~[guava-17.0.jar:?]
at com.google.common.eventbus.SynchronizedEventSubscriber.handleEvent(SynchronizedEventSubscriber.java:47) ~[guava-17.0.jar:?]
at com.google.common.eventbus.EventBus.dispatch(EventBus.java:322) ~[guava-17.0.jar:?]
at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:304) ~[guava-17.0.jar:?]
at com.google.common.eventbus.EventBus.post(EventBus.java:275) ~[guava-17.0.jar:?]
at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:147) [LoadController.class:?]
at net.minecraftforge.fml.common.Loader.initializeMods(Loader.java:828) [Loader.class:?]
at net.minecraftforge.fml.client.FMLClientHandler.finishMinecraftLoading(FMLClientHandler.java:357) [FMLClientHandler.class:?]
at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:521) [bes.class:?]
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:352) [bes.class:?]
at net.minecraft.client.main.Main.main(SourceFile:124) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_111]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_111]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_111]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_111]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_111]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_111]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_111]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_111]
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:310) [NewLaunch.jar:?]
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:394) [NewLaunch.jar:?]
at org.multimc.EntryPoint.listen(EntryPoint.java:170) [NewLaunch.jar:?]
at org.multimc.EntryPoint.main(EntryPoint.java:54) [NewLaunch.jar:?]
Caused by: java.lang.ClassNotFoundException: minetweaker.IUndoableAction
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_111]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_111]
... 45 more
Caused by: java.lang.NullPointerException
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:182) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_111]
at java.lang.ClassLoader.loadClass(Unknown Source) ~[?:1.8.0_111]
... 45 more