* delete empty line of pybing.cc, test=develop

* fix layers train eval bug, test=develop

* update, test=develop

* add paddle.

* add unittest

* add trainers for pserver

Change-Id: I1a75793ec81ce126d07f4c47cae09b95d530bbc8

* add some RecordEvent, for dygraph timeline, test=develop

* change GpuMemcpySync to memory::Copy, test=develop

* fix compile problem, test=develop

* fix compile problem, test=develop

* fix, test=develop

* fix, test=develop

* check UT Duplicate name

* fix error

* Optimized log display

* modified exit code

* add rmsprop_op_xpu test=kunlun

* modified rmsprop_op_xpu error code. test=kunlun

* unify calling cudaSetDevice

* fix compile

* support layer_norm fp16 in dygraph amp

* add ut

* refine code

* add 2.0 API: device_guard

Fix potential port conflicts

* Avoid  bug on 'MAC python3.5/6'.

* Choose the saving method according to the OS.

* smaller length of '_unpack_saved_dict' for MAC OS.

* add version information of Python.

* Edit comment.

* Collect weight threshold of lstm, test=develop

* Modify the calculation logic of LambOptimizer

* Move pass tester helper functions to single common place.

* Use helper functions in two more fuse pass tests.

* update voc url