Merge pull request #272 from FlyingQianMM/develop_qh

add __init__.py in paddlex/cv/nets/detection/loss/

paddlex/cv/nets/detection/loss/__init__.py

+# copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from . import yolo_loss
+from . import iou_aware_loss
+from . import iou_loss
+
+from .yolo_loss import *
+from .iou_aware_loss import *
+from .iou_loss import *