Support load more tensorflow operations (#1656)
Support load more tensorflow operations (#1656)

* Support load more tf operation

* refine session

* fix style issue

* meet code reivew

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