* refine PADDLE_THROW, test=develop

* refine error msg, test=develop

* refine cuda error, test=develop

* follow comments, test=develop

* fix compile problem, test=develop

* fix bug, test=develop

* add recorded cuda memory apis, fix typo, test=develop

* add more ut, test=develop

* follow comments, test=develop

* fix py35 incompatible issues, test=develop

* refine err msg of out of gpu memory, test=develop

* refine err msg again, test=develop

* refine errog message again, test=develop

* follow reviewer's comments, test=develop

* add retry_allocator for gpu, test=develop

* follow chengduoZH's comments, test=develop

* follow huihuang's comments,test=develop

* change f,l in enforce.h to be file,line, test=develop

* increase code coverage by adding unittests, test=develop

* fix CMakeLists.txt, test=develop

test=develop

* replace part of PADDLE_ASSERT to PADDLE_ENFORCE

test=develop

* remove unused fallback_alloc_size_

* add unit-test of CUDAPinnedAllocator

test=develop

* remove unnecessary set_devices

test=develop

test=develop

test=develop

* memory module

* "fix ci"