improve TFPark readme (#1684)
improve TFPark readme (#1684)

* improve readme

* fix path

* change sh to bash

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