change ImagefolderDV2 name

change ds.transforms.vision to ds.vision

change batch api to match map api more closely

compose op changes

test_pylint

remove compose op from vision, move to transform module, refactor map and batch to use column_order

Merge pull request !5888 from yoonlee666/master

Merge pull request !5599 from LiHongzhang/dataset_sink_mode

Merge pull request !5788 from zhanke/bgcf

Merge pull request !5849 from yepei6/mobilenetv2

Merge pull request !5837 from lichen/rectification_allreduce_fusion_api

Merge pull request !5827 from hwjiaorui/master

Merge pull request !5833 from wangmin0104/master

Merge pull request !5771 from jiangzhenguang/deeplabv3

Merge pull request !5782 from wangmin0104/master

Merge pull request !5767 from zhaozhenlong/lite/op/clean_codex

Merge pull request !5748 from wangmin0104/master

Merge pull request !5700 from yao_yf/mirrot_mean_to_gradients_mean

Merge pull request !5127 from hwjiaorui/master

Merge pull request !5696 from Xiaoda/20-moving-multi-graph-interface-internal

Merge pull request !5732 from yepei6/mobilenetv2_finetune

Merge pull request !5728 from wukesong/modify_init

Merge pull request !5708 from wangmin0104/master

resnet50_quant

modify readme

Merge pull request !5665 from yoonlee666/bugfix

Merge pull request !5502 from wanyiming/mod_SoftmaxCrossEntropyWithlogits

Merge pull request !5670 from wukesong/lenet_network