added movableTE's with help from @2No2Name

src/main/java/carpet/mixins/PistonBlock_movableTEMixin.java

@@ -0,0 +1,123 @@
+package carpet.mixins;
+
+import carpet.CarpetSettings;
+import carpet.fakes.PistonBlockEntityInterface;
+import com.google.common.collect.Lists;
+import net.minecraft.block.*;
+import net.minecraft.block.entity.BlockEntity;
+import net.minecraft.block.piston.PistonHandler;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Direction;
+import net.minecraft.world.World;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.Redirect;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+import org.spongepowered.asm.mixin.injection.callback.LocalCapture;
+
+import java.util.List;
+import java.util.Set;
+
+@Mixin(PistonBlock.class)
+public abstract class PistonBlock_movableTEMixin extends FacingBlock
+{
+    protected PistonBlock_movableTEMixin(Settings block$Settings_1)
+    {
+        super(block$Settings_1);
+    }
+    
+    private ThreadLocal<List<BlockEntity>> list1_BlockEntities = new ThreadLocal<>(); //Unneccessary ThreadLocal if client and server use different PistonBlock instances
+    
+    @Inject(method = "isMovable", at = @At(value = "RETURN", ordinal = 3, shift = At.Shift.BEFORE))
+    private static void movableCMD(BlockState blockState_1, World world_1, BlockPos blockPos_1,
+            Direction direction_1, boolean boolean_1, Direction direction_2, CallbackInfoReturnable<Boolean> cir)
+    {
+        Block block_1 = blockState_1.getBlock();
+        //Make CommandBlocks movable, either use instanceof CommandBlock or the 3 cmd block objects,
+        if (CarpetSettings.b_movableTileEntities && block_1 instanceof CommandBlock)
+        {
+            cir.setReturnValue(true);
+        }
+    }
+    
+    private static boolean isPushableTileEntityBlock(Block block)
+    {
+        //Making PISTON_EXTENSION (BlockPistonMoving) pushable would not work as its createNewTileEntity()-method returns null
+        return block != Blocks.ENDER_CHEST && block != Blocks.ENCHANTING_TABLE &&
+                       block != Blocks.END_GATEWAY && block != Blocks.END_PORTAL && block != Blocks.MOVING_PISTON  &&
+                       block != Blocks.SPAWNER;
+    }
+    
+    @Redirect(method = "isMovable", at = @At(value = "INVOKE", target = "Lnet/minecraft/block/Block;hasBlockEntity()Z"))
+    private static boolean ifHasBlockEntity(Block block)
+    {
+        if (!block.hasBlockEntity())
+        {
+            return !true;
+        }
+        else
+        {
+            return !(CarpetSettings.b_movableTileEntities && isPushableTileEntityBlock(block));
+        }
+    }
+    @Inject(method = "move", at = @At(value = "INVOKE", shift = At.Shift.BEFORE,
+            target = "Ljava/util/List;size()I", ordinal = 4),locals = LocalCapture.CAPTURE_FAILHARD)
+    private void onMove(World world_1, BlockPos blockPos_1, Direction direction_1, boolean boolean_1,
+            CallbackInfoReturnable<Boolean> cir, BlockPos blockPos_2, PistonHandler pistonHandler_1,
+            List<BlockPos> list_1, List<BlockState> list_2, List list_3, int int_2, BlockState blockStates_1[],
+            Direction direction_2, Set set_1)
+    {
+        //Get the blockEntities and remove them from the world before any magic starts to happen
+        if (CarpetSettings.b_movableTileEntities)
+        {
+            list1_BlockEntities.set(Lists.<BlockEntity>newArrayList());
+            for (int i = 0; i < list_1.size(); ++i)
+            {
+                BlockPos blockpos = list_1.get(i);
+                BlockEntity blockEntity = (list_2.get(i).getBlock().hasBlockEntity()) ? world_1.getBlockEntity(blockpos) : null;
+                list1_BlockEntities.get().add(blockEntity);
+                if (blockEntity != null)
+                {
+                    //hopefully this call won't have any side effects in the future, such as dropping all the BlockEntity's items
+                    //we want to place this same(!) BlockEntity object into the world later when the movement stops again
+                    world_1.removeBlockEntity(blockpos);
+                    blockEntity.markDirty();
+                }
+            }
+        }
+    }
+    
+    @Inject(method = "move", at = @At(value = "INVOKE", shift = At.Shift.BEFORE,
+            target = "Lnet/minecraft/world/World;setBlockEntity(Lnet/minecraft/util/math/BlockPos;" +
+                             "Lnet/minecraft/block/entity/BlockEntity;)V", ordinal = 0),
+            locals = LocalCapture.CAPTURE_FAILHARD)
+    private void setBlockEntityWithCarried(World world_1, BlockPos blockPos_1, Direction direction_1, boolean boolean_1,
+            CallbackInfoReturnable<Boolean> cir, BlockPos blockPos_2, PistonHandler pistonHandler_1, List list_1,
+            List list_2, List list_3, int int_2, BlockState blockStates_1[], Direction direction_2, Set set_1,
+            int int_3, BlockPos blockPos_4, BlockState blockState_1)
+    {
+        BlockEntity blockEntityPiston = PistonExtensionBlock.createBlockEntityPiston((BlockState) list_2.get(int_3),
+                direction_1, boolean_1, false);
+        if (CarpetSettings.b_movableTileEntities)
+            ((PistonBlockEntityInterface) blockEntityPiston).setCarriedBlockEntity(list1_BlockEntities.get().get(int_3));
+        world_1.setBlockEntity(blockPos_4, blockEntityPiston);
+    }
+    
+    @Redirect(method = "move", at = @At(value = "INVOKE",
+            target = "Lnet/minecraft/world/World;setBlockEntity(Lnet/minecraft/util/math/BlockPos;" +
+                             "Lnet/minecraft/block/entity/BlockEntity;)V",
+            ordinal = 0))
+    private void dontDoAnything(World world, BlockPos blockPos_6, BlockEntity blockEntityPiston)
+    {
+    }
+    
+    @Redirect(method = "move", at = @At(value = "INVOKE",
+            target = "Lnet/minecraft/block/PistonExtensionBlock;createBlockEntityPiston(Lnet/minecraft/block/BlockState;" +
+                             "Lnet/minecraft/util/math/Direction;ZZ)Lnet/minecraft/block/entity/BlockEntity;",
+            ordinal = 0))
+    private BlockEntity returnNull(BlockState blockState_1, Direction direction_1, boolean boolean_1, boolean boolean_2)
+    {
+        return null;
+    }
+}