Add limited support for Thaumcraft essentia containers

Item stacks of Thaumcraft items, such as esssentia jars, are a
pain to work with if you can't see their contents. The contents
are not hidden by Thaumcraft, so showing them isn't cheaty.

Making these available makes it possible to use OC to sort
essentia jars by contents, which is SUPER USEFUL since everything
else I have which sorts inventory ignores them.

this work was adjusted from PR #2942 by user @seebs

src/main/scala/li/cil/oc/integration/Mods.scala

@@ -35,6 +35,7 @@ object Mods {
   val ProjectRedTransmission = new SimpleMod((IDs.ProjectRedTransmission))
   val DraconicEvolution = new SimpleMod(IDs.DraconicEvolution)
   val EnderStorage = new SimpleMod(IDs.EnderStorage)
+  val Thaumcraft = new SimpleMod(IDs.Thaumcraft)
 
   // ----------------------------------------------------------------------- //
 
@@ -52,6 +53,7 @@ object Mods {
     integration.projectred.ModProjectRed,
     integration.computercraft.ModComputerCraft,
     integration.enderstorage.ModEnderStorage,
+    integration.thaumcraft.ModThaumcraft,
 
     // We go late to ensure all other mod integration is done, e.g. to
     // allow properly checking if wireless redstone is present.
@@ -97,6 +99,7 @@ object Mods {
     final val ProjectRedTransmission = "projectred-transmission"
     final val DraconicEvolution = "draconicevolution"
     final val EnderStorage = "enderstorage"
+    final val Thaumcraft = "thaumcraft"
   }
 
   // ----------------------------------------------------------------------- //

src/main/scala/li/cil/oc/integration/thaumcraft/ConverterThaumcraftItems.scala

@@ -0,0 +1,47 @@
+package li.cil.oc.integration.thaumcraft
+
+import java.util
+
+import li.cil.oc.api.driver.Converter
+import net.minecraft.item.{Item, ItemStack}
+import net.minecraft.nbt.NBTTagCompound
+import net.minecraftforge.common.util.Constants.NBT
+
+import scala.collection.convert.WrapAsScala._
+import scala.collection.mutable
+
+object ConverterThaumcraftItems extends Converter {
+  override def convert(value: scala.Any, output: util.Map[AnyRef, AnyRef]): Unit = value match {
+    case stack: ItemStack =>
+      val name = Item.REGISTRY.getNameForObject(stack.getItem).toString
+
+      // Handle essentia/vis contents for Thaumcraft jars, phials, and crystals
+      if ((name == "thaumcraft:jar_normal") ||
+          (name == "thaumcraft:jar_void") ||
+          (name == "thaumcraft:phial") ||
+          (name == "thaumcraft:crystal_essence")) {
+        if (stack.hasTagCompound &&
+          stack.getTagCompound.hasKey("Aspects", NBT.TAG_LIST)) {
+          val aspects = mutable.ArrayBuffer.empty[mutable.Map[String, Any]]
+          val nbtAspects = stack.getTagCompound.getTagList("Aspects", NBT.TAG_COMPOUND).map {
+            case tag: NBTTagCompound => tag
+          }
+          for (nbtAspect <- nbtAspects) {
+            val key = nbtAspect.getString("key")
+            val amount = nbtAspect.getInteger("amount")
+            val aspect = mutable.Map[String, Any](
+              "aspect" -> key,
+              "amount" -> amount
+            )
+            aspects += aspect
+          }
+          output += "aspects" -> aspects
+        }
+        if (stack.hasTagCompound && stack.getTagCompound.hasKey("AspectFilter", NBT.TAG_STRING)) {
+          output += "aspectFilter" -> stack.getTagCompound.getString("AspectFilter")
+        }
+      }
+
+    case _ =>
+  }
+}

src/main/scala/li/cil/oc/integration/thaumcraft/ModThaumcraft.scala

@@ -0,0 +1,13 @@
+package li.cil.oc.integration.thaumcraft
+
+import li.cil.oc.api.Driver
+import li.cil.oc.integration.ModProxy
+import li.cil.oc.integration.Mods
+
+object ModThaumcraft extends ModProxy {
+  override def getMod: Mods.ModBase = Mods.Thaumcraft
+
+  override def initialize() {
+    Driver.add(ConverterThaumcraftItems)
+  }
+}