* add some debug flags to auto growth allocator, test=develop

* add comments about auto growth, test=develop

* fix -Wno-error=sign-compare warning in gcc8

test=develop

* fix warning in distributed codes

test=develop

* use system allocator in unittests, test=develop

* fix op bugs, test=develop

* fix tensor copy bug when src and dst are the same, test=develop

TemporaryAllocator is a singleton used for allocating memory for Cudnn. Since it is a singleton, we can delete it for better performance in memory.

We replace TemporaryAllocator by CUDADeviceContextAllocator and CUDADeviceContextAllocation, which uses stream callback to delete the memory allocated for the stream to avoid singleton.

Also added data_feed_proto to operator to fix CI in CPU compilation

* 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

* feature/auto_growth_allocator, test=develop

* add unittest of AlignedAllocator, test=develop

* try to turn on auto_growth to test on CI, test=develop

* fix segmentation fault in mixed_vector.h, test=develop

* add unittests, test=develop

* delete m, test=develop

test=develop

As title

test=develop

* remove attribute in Allocator::Allocate, test=develop

* fix travis ci error, test=develop

* Revert "Revert "Fix allocator bug""

This reverts commit 174d0d0b.

* Revert "fix travis ci"

This reverts commit 5656fa9f.

test=develop

* add inlined_vector.h, test=develop

* add inlined_vector_test,test=develop

* clean code of allocator,test=develop

* delete zero_size_allocator.h,test=develop

* fix failed unittest,test=develop

* Revert "Revert "Fix allocator bug""

This reverts commit 174d0d0b.

* Revert "fix travis ci"

This reverts commit 5656fa9f.

test=develop

* add inlined_vector.h, test=develop

* add inlined_vector_test,test=develop

test=develop

* remove unnecessary set_devices

add include headers to fix travis-ci
test=develop

test=develop

test=develop

test=develop

modify allocator strategy
remove changes of legacy buddy_allocator
test=develop

test=develop

test=develop

test=develop

* Remove Desc in Forward Pass

* Refactor VarBase

* Add dbg info

* Only check type in imperative mode

* Polish code and support optimizer

test=develop

* Fix stop gradient problem in PyLayer

test=develop

test=develop