add Threshold and AveragePooling1D (#426)
add Threshold and AveragePooling1D (#426)

* add Threshold and AveragePooling1D

* update

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