Various Fixes (Nukkit#266)

- No water from broken packed ice
- Anvil can now be placed on snow layer
- Fix dead bush turning to update block if replaced with other block

Everything tested and works

(cherry picked from commit f1b33cd)

src/main/java/cn/nukkit/block/BlockAnvil.java

@@ -89,7 +89,7 @@ public String getName() {
 
     @Override
     public boolean place(Item item, Block block, Block target, BlockFace face, double fx, double fy, double fz, Player player) {
-        if (!target.isTransparent()) {
+        if (!target.isTransparent() || target.getId() == Block.SNOW_LAYER) {
             int damage = this.getDamage();
             int[] faces = {1, 2, 3, 0};
             this.setDamage(faces[player != null ? player.getDirection().getHorizontalIndex() : 0]);

src/main/java/cn/nukkit/block/BlockDeadBush.java

@@ -31,6 +31,11 @@ public String getName() {
     public int getId() {
         return DEAD_BUSH;
     }
+
+    @Override
+    public boolean canBeReplaced() {
+        return true;
+    }
 
     @Override
     public boolean place(Item item, Block block, Block target, BlockFace face, double fx, double fy, double fz, Player player) {

src/main/java/cn/nukkit/block/BlockIcePacked.java

@@ -1,5 +1,6 @@
 package cn.nukkit.block;
 
+import cn.nukkit.item.Item;
 import cn.nukkit.item.ItemTool;
 
 /**
@@ -35,4 +36,10 @@ public int onUpdate(int type) {
     public boolean canHarvestWithHand() {
         return false;
     }
+
+    @Override
+    public boolean onBreak(Item item) {
+        this.getLevel().setBlock(this, new BlockAir(), true); //no water
+        return true;
+    }
 }