make Tabs.fresh() return the graph div when creating a plot tab:
make Tabs.fresh() return the graph div when creating a plot tab:

- this is to ensure that old Plotly.plot test scripts are still
  functional.

iongroup/plotly.js,plotly/plotly.js,aburato/plotly.js,etpinard/plotly.js,etpinard/plotly.js,asolagmbh/plotly.js,asolagmbh/plotly.js,iongroup/plotly.js,plotly/plotly.js,etpinard/plotly.js,plotly/plotly.js,aburato/plotly.js,asolagmbh/plotly.js,plotly/plotly.js,iongroup/plotly.js