replace labelstower package name to new name ('labelstower' for package and distribution)

test/demo_flask/__init__.py

@@ -25,7 +25,7 @@ def create_app():
 
     app.config.from_object(os.environ['LABELSTOWER_ENV'])
 
-    from app.labels_system import bp
+    from labelstower import bp
     app.register_blueprint(bp, url_prefix='/sort')
 
     @app.route('/')