c implementation done, just need to call batch/pad

added python api and validator

added pybind/de_pipeline stuff, fixed some compile errors, figure out how null py::function works

added tiny bit of doc

integrated with static batch methods

fixed some bugs

some more bug fixes and cleanup

ci fix

fix ci

ci fix

fix ci

added test_cases and debugged

addressed code review comments

addressed code review comments

ci fix

ci fix

addressed code review comments

addressed code review comments

- Support accepting Numpy of str as input
- Support batching strings
- Core logic of batch&pad is static
- Make Pad a utility function

clang format updates

self-review cleanups

cpplint fix

review updates

ci fixes

support for 1 specific dimension to be None, added validator

fix various CI complains

another round of CI fixes

ci

refactor parts of the code

code refactor

ci fix

comments added, fix bugs

address review comments

address review comments

review cmts

added simple perf test script

update pad code

perf imprv

fix clang

pybind fix

Signed-off-by: leonwanghui <leon.wanghui@huawei.com>