Dim<0> is for scalar (rank-0 tensor). Adding Dim<0> can simplify
a lot of code.

remove `import paddle.fluid` in conf.py.in

combine batch_size_like.cc into batch_size_like.h

* merge fluid dist tests

* update cmake

add warrper for detection map operator

Update conll05.py

* Fix dist demo error

* revert trainer_id

Extend current profiler for timeline and more features.

Tensorflow benchmark

Refine cmake for cudnn op

* Enhance bipartite_match_op to support argmax matching after bipartite matching.

* Fix typo error.

Refine the inference API and unittests

set the default option of WITH_FAST_BUNDLE_TEST be OFF

Fix send_recv unit test

Fix c-api doc style

* "try enhance concat op"

* "enhance the concat operator"

Fix the bug of conv2d 

fix short connection again

fix warp ctc dir error

add c-api quick start

Enhance layer_function_generator