Replace lod with recursive_sequence_lengths in book examples

optimize doc for host_memory_profiling_cn

fix mac compile

add timeline_cn

make framework.Parameter public

* Fix mean iou op.

* Fix crop layer test.

* Fix unitest

* fix unitest.

* Fix average_accumulate_op for parallel executor.

* Fix model average on multi-GPUs.

* hack deadline to fix timeout

* add fixme

[cherry-pick]change predictions to preds

[cherry-pick] Fix async update

[cherry-pick] fix pserver optimize blocks

Merge pull request #11728 from typhoonzero/fix_paraexe_bcast

Fix dist train broadcasting bug

[cherry-pick] fix sparse update in parallelExecutor

fix pserver sub-blocks

fix sparse paraexe dist train

Fix async update failed

Update api.rst (merge to release/0.14.0)

Fix kill fail bug (#11635)

* 1. Remove PYTHON_FLAGS from paddle_build.sh in paddlepaddle/paddle:latest-dev

* 1. Add PYTHON_FLAGS back
2. Change SIGKILL to SIGINT and SIGTERM

* 1. Add setup.py.in back

* 1. add pip install open-cv in Dockerfile to avoid libusb_exit hanging up which is caused by the opencv-python package missing

* 1. Add the && \ to line above

* 1. Remove the notice comment

cherry-pick: fix indentation error

* Fix Parallel Exe(VarHandel's version)

* Fix broadcast

* enhance ParallelExecutor stable

Merge pull request #11622 from panyx0718/doc

disable the LODTensor warning for now

Cherry Pick the documentation PRs.

* "add some api reference"

* "fix based on preview"

* "fix evaluator"

* "remove template doc"

* "add doc for exec"

* "add more changes"

* "fix based on preview"

* "chagne code format"

Merge pull request #11608 from panyx0718/doc

small thread-safety fix and doc improvements.