pull dev for v0.4.1

add DSIN
refactor layers

change dtype string to str of numpy&pandas object

feat:add FGCNN&FGCNNLayer

Update CCPM_test.py

Update dien.py

add a global variable initializer op in model def

fix

Update feature config generation method & Fix bugs

- Adopted a new feature config generation method
- Simplified input mechanism for multi-valued features.
- Fix bug: in some cases the order of model input placeholder and actual model input list does not match.
- Fix bug: Divide by zero overflow in `SequencePoolingLayer` when sequence length is 0.

Refactor & Add sequence input support

* Refactor Input&Embedding

* Support sequence(multi-value) input for AFM,AutoInt,DCN,DeepFM,FNN,NFM,PNN,xDeepFM models

Update for v0.2.1

* Add AutoInt & InteractingLayer

Release v0.2.0