Implement StringTag, run autofix

lib/nbt/Tag.dart

@@ -12,6 +12,7 @@ import 'Stream.dart';
 import 'impl/ByteTag.dart';
 import 'impl/ListTag.dart';
 import 'impl/LongArrayTag.dart';
+import 'impl/StringTag.dart';
 
 enum TagType {
   End(0),
@@ -59,7 +60,7 @@ abstract class Tag {
   static Tag readNamedTag(ByteLayer data) {
     var type = data.readByte();
     if (type == 0) {
-      return new EndTag();
+      return EndTag();
     } else {
       Tag tag = makeTagOfType(TagType.get(type));
       tag._key = data.readString();
@@ -78,63 +79,72 @@ abstract class Tag {
   }
 
   bool equals(dynamic object) {
-    if (object == null || !(object is Tag)) return false;
+    if (object == null || object is! Tag) return false;
 
     Tag tag = object;
     if (tag.getType() != getType()) return false;
 
-    if (getKey() == null && tag.getKey() != null ||
-        tag.getKey() == null && getKey() != null) return false;
-
-    if (getKey() != null && !(getKey() == tag.getKey())) return false;
+    if (!(getKey() == tag.getKey())) return false;
 
     return true;
   }
-  
+
   static Tag makeTagOfType(TagType type) {
     switch (type) {
       case TagType.Byte:
         {
-          return new ByteTag();
+          return ByteTag();
         }
       case TagType.ByteArray:
         {
-          return new ByteArrayTag();
+          return ByteArrayTag();
         }
 
       case TagType.Compound:
         {
-          return new CompoundTag();
+          return CompoundTag();
         }
       case TagType.Double:
         {
-          return new DoubleTag();
+          return DoubleTag();
         }
       case TagType.End:
-        return new EndTag();
+        {
+          return EndTag();
+        }
       case TagType.Short:
-        return new ShortTag();
+        {
+          return ShortTag();
+        }
       case TagType.Int:
-        return new IntTag();
+        {
+          return IntTag();
+        }
       case TagType.Long:
-        return new LongTag();
+        {
+          return LongTag();
+        }
       case TagType.Float:
-        return new FloatTag();
+        {
+          return FloatTag();
+        }
       case TagType.IntArray:
         {
-          return new IntArrayTag();
+          return IntArrayTag();
         }
       case TagType.LongArray:
         {
-          return new LongArrayTag();
+          return LongArrayTag();
         }
 
       case TagType.List:
         {
-          return new ListTag();
+          return ListTag();
+        }
+      case TagType.String:
+        {
+          return StringTag();
         }
-      }
     }
   }
-
 }