add build_neck and build_loss in model.__init__ (#237)

Author: dreamerlin

mmaction/models/__init__.py

@@ -1,8 +1,8 @@
 from .backbones import (ResNet, ResNet2Plus1d, ResNet3d, ResNet3dCSN,
                         ResNet3dSlowFast, ResNet3dSlowOnly, ResNetTIN,
                         ResNetTSM)
-from .builder import (build_backbone, build_head, build_localizer, build_model,
-                      build_recognizer)
+from .builder import (build_backbone, build_head, build_localizer, build_loss,
+                      build_model, build_neck, build_recognizer)
 from .common import Conv2plus1d
 from .heads import BaseHead, I3DHead, SlowFastHead, TPNHead, TSMHead, TSNHead
 from .localizers import BMN, PEM, TEM
@@ -20,5 +20,6 @@
     'ResNet3dSlowFast', 'SlowFastHead', 'Conv2plus1d', 'ResNet3dSlowOnly',
     'BCELossWithLogits', 'LOCALIZERS', 'build_localizer', 'PEM', 'TEM',
     'BinaryLogisticRegressionLoss', 'BMN', 'BMNLoss', 'build_model',
-    'OHEMHingeLoss', 'SSNLoss', 'ResNet3dCSN', 'ResNetTIN', 'TPN', 'TPNHead'
+    'OHEMHingeLoss', 'SSNLoss', 'ResNet3dCSN', 'ResNetTIN', 'TPN', 'TPNHead',
+    'build_loss', 'build_neck'
 ]