Resolves #146 Lock support

lib/entity_widgets/state/lock_state.dart

@@ -0,0 +1,32 @@
+part of '../../main.dart';
+
+class LockStateWidget extends StatelessWidget {
+
+  void _lock(Entity entity) {
+    eventBus.fire(new ServiceCallEvent("lock", "lock", entity.entityId, null));
+  }
+
+  void _unlock(Entity entity) {
+    eventBus.fire(new ServiceCallEvent("lock", "unlock", entity.entityId, null));
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final entityModel = EntityModel.of(context);
+    final LockEntity entity = entityModel.entityWrapper.entity;
+    return SizedBox(
+      height: 34.0,
+      child: FlatButton(
+        onPressed: (() {
+          entity.isLocked ? _unlock(entity) : _lock(entity);
+        }),
+        child: Text(
+          entity.isLocked ? "UNLOCK" : "LOCK",
+          textAlign: TextAlign.right,
+          style:
+          new TextStyle(fontSize: Sizes.stateFontSize, color: Colors.blue),
+        ),
+      )
+    );
+  }
+}