Removes coremod (#3038)

From now on every integration must not rely on method stripping through
a coremod or @Optional. Notable example for a very good solution is IC2.

As consequence this drops all support for RF and mods must support on of
our supported energy types. At the time of writing, ForgeEnergy and
IC2/EU.

src/main/java/appeng/client/ClientHelper.java

@@ -62,7 +62,6 @@ import appeng.core.AppEng;
 import appeng.core.sync.network.NetworkHandler;
 import appeng.core.sync.packets.PacketAssemblerAnimation;
 import appeng.core.sync.packets.PacketValueConfig;
-import appeng.coremod.MissingCoreMod;
 import appeng.entity.EntityFloatingItem;
 import appeng.entity.EntityTinyTNTPrimed;
 import appeng.entity.RenderFloatingItem;
@@ -241,12 +240,6 @@ public class ClientHelper extends ServerHelper
 		mc.world.markBlockRangeForRenderUpdate( x - range, y - range, z - range, x + range, y + range, z + range );
 	}
 
-	@Override
-	public void missingCoreMod()
-	{
-		throw new MissingCoreMod();
-	}
-
 	@SubscribeEvent
 	public void postPlayerRender( final RenderLivingEvent.Pre p )
 	{