remove graphengine changes

concat op

Truncate Pair

concat_op

remove graph engine changes

ToNumberOp implementation almost done

ToNumberOp complete

ci fix

ci fix

ci fix

ci fix

ci fix

ci fix

ci fix

ci fix

ci fix

ci fix

merge conflicts

remove graphengine changes

concat op

Truncate Pair

concat_op

remove graph engine changes

Merge pull request !2211 from h.farahat/pair_truncate

Merge pull request !1993 from luoyang/pylint

- Add new CreateTensors

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

add support for MindRecord and TFRecord
----
optimize tensorshape

optimize tensorshape and FlatIndex

TFRecord and MindRecord support for string tensor

Modify mem layout
Add new constructor
Add method Allocate

Change some GetMutableBuffer usages to AllocateBuffer

-replace switch'case by indexing

- Add test case
- Add constructors
- Add getItem string

- Fix bugs
- Add more tests

- Tensor iterator
- asNumpy
- TextFileDataset

- Tensor(Numpy)

- Super > 2D
- Add more test cases for GeneratorDataset

- Change StartAddr to GetBuffer and GetMutableNuffer

- Raise an error if batch is used with strings

Clean-up work

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