added movableTE's with help from @2No2Name

src/main/java/carpet/fakes/PistonBlockEntityInterface.java

@@ -0,0 +1,12 @@
+package carpet.fakes;
+
+import net.minecraft.block.entity.BlockEntity;
+
+public interface PistonBlockEntityInterface
+{
+    void setCarriedBlockEntity(BlockEntity blockEntity);
+    BlockEntity getCarriedBlockEntity();
+    void setRenderCarriedBlockEntity(boolean b);
+    boolean getRenderCarriedBlockEntity();
+    boolean isRenderModeSet();
+}