Merge branch 'develop' of https://github.com/PaddlePaddle/Paddle into fix-optimizer-accumulator

python/paddle/fluid/__init__.py

@@ -65,7 +65,7 @@ __all__ = framework.__all__ + executor.__all__ + concurrency.__all__ + \
               'io',
               'initializer',
               'layers',
-              'transpiler'
+              'transpiler',
               'nets',
               'optimizer',
               'learning_rate_decay',