* test=develop,Fix communicator slow bug

* test=develop, delete if() in stop_worker()

* test=develop

* fix UT, test=develop

* fix bug in fetch handler, test=develop

* fix bug in fetch handler, test=develop

* test=develop, fix fetch barrier bug

* test=develop, bug fix

* test=develop, bug fix

* test=develop, fix bug

add executor.FetchHandler for train/infer from the dataset

* fix save/load in Fleet
* add UT framework of Fleet

test=develop

* add dist ut for text_classification

* add dist ut for text_classification

* add simnet bow unittest

* add dist ut for simnet bow

* add trainning data url for simnet bow

* add trainning data url for simnet bow

* modify simnet test_reader to train reader

* add test_dist_ctr

* test_dist_ctr can run now

* dense update is good

* add unit test for selected rows

* debug unit test

* fix dist sparse update problem

* Constant args at init

* optimize code

* simnet optimize

* fix DebugStringEx

* optimize sum_op.h

* add ScaleOpVarTypeInference

* clean code

* fix test_dist_transpiler.py

* code optimize

* modify delta

* fix sparse update bug

* dist test use one cpu

* update some data

* remove unused code

* add use cuda config

* unit test fix

* unit test fix

* unit test fix

* unit test fix

* dist_word2vec use CPU

* unit test fix

* unit test fix

* code clean

* code clean

* merge develop

* api spec update

* Revert: api spec update

* replace simnet data with fake

* replace simnet data with fake

* update dim

* add batch auc

* code clean

* code clean

* modify print to stderr

* update simnet delta -> 1e-5

* update RUN_STEP

* add use_reader_alloc

* add use_reader_alloc

* add use_reader_alloc

* modify delta

* add use_reader_alloc

* fix stderr write

* python3 compatibility

test=develop

* python3 compatibility, test=develop

* Update dist_text_classification.py

* test=develop