fix mac compile error in subgraph_splitter

* Enhence generate_proposal_labels_op
* Fix bug in generate_proposals_op
* Refine rpn_target_assign_op.
* by Bu Xingyuan, Wang Guanzhong and Dang Qingqing

move bcast op into graph passes

fix fluid_benchmark resnet lr decay

Fix tensorrt subgraph bug

add multi-thread for nlp unit-tests

Support grouped convolution layer with mkldnn.

hotfix for conv-relu pass

fix with distribute cmake

* trainer auto wait pserver port ready

* add file

* fix docstring

* add option to not wait

* update api spec

* clean

* fix test hang

add analyzer_rnn2_test

disable seqexpandconcatfc op test on Mac

fix mac test_reader_reset

fix mac test_data_balance

import os module to use os.environ in setUp()

fix fusion_lstm unique_name bug