* add 1f1b scheduler for pp, test=develop

* remove the send/recv of tensor size, but users have to specify the shape of the received var explicitly.

* update, test=develop

* update, test=develop

* update, test=develop

* fix fleet util and gloo

* fix worker endpoints

* fix

* fix UT

* fix gloo

* fix gloo

* update gloo

* update gloo

* update gloo

* update gloo

* update gloo

* fix gloo wrapper for hdfs

* add file gloo and UT

* fix UT

* fix UT

* fix UT

* hide public method of RoleMaker

* fix UT

* GPU fleetrun support gloo

* parameterserver fleetrun support gloo

* add UT

* add UT

* fix UT

* fix get server endpoint

* fix get server endpoint

* fix UT

* hide public method of rolemaker

* hide public method of rolemaker

* hide public method of rolemaker

* Update test_fleet_rolemaker_new.py

* hide public method of rolemaker

* hide public method of rolemaker

* parameter_server_optimizer support auto_strategy

* add auto parallel L1 implementation
test=develop

* fix api document

* consider the combination of different strategies to work together

* add check approval
test=develop

* move paddle.fleet to paddle.distributed.fleet

* add the support for multi-node training

* add pipeline optimizer

* refine strategy compiler and meta optimizers
make async as a_sync

refactor fleet api under paddle.fleet
update DistributedStrategy