Resolves #146 Lock support

lib/entity_class/lock_entity.class.dart

@@ -0,0 +1,12 @@
+part of '../main.dart';
+
+class LockEntity extends Entity {
+  LockEntity(Map rawData) : super(rawData);
+
+  bool get isLocked => state == "locked";
+
+  @override
+  Widget _buildStatePart(BuildContext context) {
+    return LockStateWidget();
+  }
+}