Change the inference example to an unittest

* add basic interface for learning rate decay
* add exponential_decay
* add natural_exp_decay
* add inverse_time_decay

* "unify flags"

* "fix init"

Add CPU implementation of layer normalization operator.

* Add save_combine_op

* Add load_combine_op and test

* Add unit-test

* Add a delete to free buffer memory

* Add new variant of load/save

* Fix unit-test

* Add another unit test for compatibility with original save/load

* Address review comments and simplify logic

* Address review comments and simplify code - part 2

* Fix naming issues and CMake problems

* Address review comments

* Fix LoD information in tests

* Address review comments: round 2

Performance enhancement by reuse connection

fix the bug that dropout always uses a fixed seed.

Add label smooth operator.

* Initial commit

* Remove resolution bug

* Modify IsParam

* Remove small bugs

* First commit unifying Run and Load

* Fix bugs

* Fix Cmake

* Modify Cmake and dir structure

* Add io.* files to inference dir

* Fix include in example

* Address review comments: part 1

* Address review comments: round 2

* Address review comments: round 3

* Address review comments: round 4

Refine debug string of Parameter

Fix 5902

Enable whole-archive flag in cc_test and use cc_test to rewrite the CMakeLists.txt of inference unittest.

* refine channel test

* follow comments

* Add dependency enforce to threadpool

* Revert changes to channel_test.cc

* Revert changes to channel_test.cc

* Add #include "paddle/framework/macros.h"

Remove unreferenced variables from ProgramDesc in prune()

Bug fix for sequence_reshape operator.

Add weight normalization wrapper.

add docstring for set_gradient_clip

* initialize batch barrier

* add some comments

* update

* fix batch barrier

* use sendvariable rpc interface to send batch barrier

* fix comment

* fix method

* fix by comment

* fix by comment

Add build_type to build.sh