Multiple crashes using Energy Cell and Energy pipes.

[DrUltraLux]

I am getting frequent crashes when attempting to get energy systems working. Also seems to frequently just stop transferring energy into the network.
Also often have to delete the config file after a crash or forge black screens.

[DrUltraLux]

Found one of the problems.

[Netty Server IO #1/ERROR]: There was a critical exception handling a packet on channel gadgetrycore
io.netty.handler.codec.EncoderException: java.lang.RuntimeException: Undefined discriminator for message type epicsquid.gadgetry.core.network.MessageTEUpdate in channel gadgetrycore
	at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:106) ~[MessageToMessageEncoder.class:4.1.9.Final]
	at io.netty.handler.codec.MessageToMessageCodec.write(MessageToMessageCodec.java:116) ~[MessageToMessageCodec.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:738) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:801) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:814) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:794) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:831) ~[AbstractChannelHandlerContext.class:4.1.9.Final]
	at io.netty.channel.DefaultChannelPipeline.writeAndFlush(DefaultChannelPipeline.java:1032) ~[DefaultChannelPipeline.class:4.1.9.Final]
	at io.netty.channel.AbstractChannel.writeAndFlush(AbstractChannel.java:296) ~[AbstractChannel.class:4.1.9.Final]
	at net.minecraftforge.fml.common.network.simpleimpl.SimpleNetworkWrapper.sendToAll(SimpleNetworkWrapper.java:236) ~[SimpleNetworkWrapper.class:?]
	at epicsquid.gadgetry.core.EventManager.onServerTick(EventManager.java:81) ~[EventManager.class:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_2025_EventManager_onServerTick_WorldTickEvent.invoke(.dynamic) ~[?:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) ~[ASMEventHandler.class:?]
	at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182) ~[EventBus.class:?]
	at net.minecraftforge.fml.common.FMLCommonHandler.onPostWorldTick(FMLCommonHandler.java:274) ~[FMLCommonHandler.class:?]
	at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:776) ~[MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) ~[MinecraftServer.class:?]
	at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:185) ~[chd.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) ~[MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_51]
Caused by: java.lang.RuntimeException: Undefined discriminator for message type epicsquid.gadgetry.core.network.MessageTEUpdate in channel gadgetrycore
	at net.minecraftforge.fml.common.network.FMLIndexedMessageToMessageCodec.encode(FMLIndexedMessageToMessageCodec.java:76) ~[FMLIndexedMessageToMessageCodec.class:?]
	at io.netty.handler.codec.MessageToMessageCodec$1.encode(MessageToMessageCodec.java:67) ~[MessageToMessageCodec$1.class:4.1.9.Final]
	at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:88) ~[MessageToMessageEncoder.class:4.1.9.Final]
	... 19 more

[DrUltraLux]

Problem is here.
Sometimes it is attempting to write a Null tag to the ByteBuff.

Should put an if(tag) or try() around the buffer write.

https://github.com/MysticMods/GadgetryCore/blob/master/src/main/java/epicsquid/gadgetry/core/network/MessageTEUpdate.java