The basic idea is: exploits data dependency to control the execution order
of side-effect operations, and keep the semantics of ANF unchanged.

The ControlDepend primitive is removed and there are two primitives added:

1. UpdateState:
```
  a = Assign(para, value)
```
became:
```
  a = Assign(para, value, u)
  u = UpdateState(u, a)
```

2. Load:
```
  x = Add(para, value)
```
became:
```
  p = Load(para, u)
  x = Add(p, value)
  u = UpdateState(u, p)
```

Merge pull request !7339 from qujianwei/master

Merge pull request !5239 from zhaoting/master

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 !5502 from wanyiming/mod_SoftmaxCrossEntropyWithlogits

Merge pull request !5350 from lichen/rectification_init

Merge pull request !4362 from qujianwei/master

Merge pull request !3719 from RobinGrosman/master

2) label smoothign for GPU
3) dataset chagnes for resnset101 GPU