* init commit

* fix tensor operator*

* fix compile bug

* bug reproduce

* update commit

* polish codes

* fix compile bug

* test begin

* test begin

* compile finish

* restore origin composite_backward_api

* pass local CI

* fix merge error

* fix merge error

* change py_test from GPU->CPU, test custom op

* polish codes, modify prim unittest

* modify prim unittest

* determine phi_tensor_operants location

* polish codes

* add header file

* solve windows unresolved symbol

* fix some CI error

* add overload defination

* fix CI inference and Windows

* polish codes according to reviewers' opinion

* polish codes according to reviewers' opinion

* use iwyu clean include, test=develop, test=win

* compilation error, test=develop

* fix compilation error2, test=develop

* fix compilation error3, test=develop

* fix compilation error4, test=develop

* fix compilation error5, test=develop

* fix compilation error6, test=develop

* fix compilation error7, test=develop

* fix compilation error8, test=develop

* fix compilation error8, test=develop

* fix compilation error10, test=develop

* fix compilation error11, test=develop

* modify the interface of Pass::Allay
test=develop

* Polish code
test=develop

* Fix Travis CI
test=develop

* fix Pass::Apply interface
test=develop

* Fix Travis CI
test=develop

and #pragma once in edited headers

add #include<string> in edited headers

test=develop

* link IR graph to analysis graph

* add clean code and update

* add infer_clean_pass

* add ir_pass_manager

* support fc fuse executation

* fix ir circle

Reduce one level of inheritence.

add doc

* Use Builder Chain to decorate new builders. It is easy to extend
  builders.
* Make graphviz path as a build strategy, not a FLAGS.

* cpplint test and add tesnor_py_test.cc

* Update

* Update

* Update tensor_util.h

* Update with moved TensorDesc

* Fix tensur_utils.cu

* Update

* Update

* Update

* Update

* Make tensor_util.cu a symbolic link