Patch DimensionSavedDataManager to not spam FS mkdirs requests for

empty files that don't exist yet, and don't contain data. Should
result in a significant performance improvement for those with slower disks.

Signed-off-by: cpw <cpw+github@weeksfamily.ca>

src/main/java/net/minecraftforge/common/util/DummyWorldSaveData.java

@@ -0,0 +1,22 @@
+package net.minecraftforge.common.util;
+
+import net.minecraft.nbt.NBTTagCompound;
+import net.minecraft.world.storage.WorldSavedData;
+
+public class DummyWorldSaveData extends WorldSavedData {
+    public static final DummyWorldSaveData DUMMY = new DummyWorldSaveData();
+    private DummyWorldSaveData() {
+        super("DUMMYDUMMY \uD83D\uDC4C\uD83D\uDC4C\uD83D\uDC4C");
+    }
+
+    @Override
+    public void read(final NBTTagCompound nbt) {
+        // NOOP
+    }
+
+    @Override
+    public NBTTagCompound write(final NBTTagCompound compound) {
+        // NOOP
+        return null;
+    }
+}