Init the strcuture for supporting keras 2.1.6 (#320)
Init the strcuture for supporting keras 2.1.6 (#320)

* add keras2.1.6

* add gen scripts

* style and test

* add tags for keras2

* refactor the structure

* style

* add keras

* clean

intel-analytics/BigDL,yangw1234/BigDL,intel-analytics/BigDL,yangw1234/BigDL,intel-analytics/BigDL,intel-analytics/BigDL,yangw1234/BigDL,yangw1234/BigDL