* change fluid.mean to paddle.mean

* reverse some old code examples

* use yapf to format all python file

* yapf exclude two unittests file for they rely on writing and reading file, and format will break them

* disable diff_py_file because too many diff files cause command following failed

* default open dygraph mode

* fix CI-Mac

* fix Mac-CI other unittest file

* fix CI-Py3

* fix test_communicator_geo and test_buffer_shared_memory_reuse_pass

* add enable_static to fix CI-Py3

* add enable_static to fix CI-coverage

* delete try except

* add mul and matmul quantization, test=develop
* add test for matmul, test=develop

* Fix bug for inserting add_quant_dequant_op to same variable repetitively in add_quant_dequant_pass, test=develop

* move pool2d to add_quant_dequant_pass, test=develop

* add fake_quant_dequant_op for average pool2d
* add test

* add pool2d quantization support, only for max-pooling.

* add the partial quantization support.

* Add moving average absmax op in quantilize-aware training.