Updated to handle networkx 2.0 Views (#6972)
Updated to handle networkx 2.0 Views (#6972)

* Updated to handle networkx 2.0 Views

This is not backward compatible Views were added in nx 2.0

* Added handling for nx 1.x and 2.x

* Changes to handling  for nx 1 and 2

Wrap graph nodes and edges in list for conversion to CDS(s)

* Handle nx 1.0 and 2.0

ericmjl/bokeh,jakirkham/bokeh,philippjfr/bokeh,rs2/bokeh,jakirkham/bokeh,timsnyder/bokeh,ericmjl/bokeh,rs2/bokeh,dennisobrien/bokeh,Karel-van-de-Plassche/bokeh,ericmjl/bokeh,rs2/bokeh,aavanian/bokeh,rs2/bokeh,aavanian/bokeh,dennisobrien/bokeh,timsnyder/bokeh,ericmjl/bokeh,stonebig/bokeh,jakirkham/bokeh,aavanian/bokeh,bokeh/bokeh,mindriot101/bokeh,philippjfr/bokeh,aavanian/bokeh,aavanian/bokeh,Karel-van-de-Plassche/bokeh,bokeh/bokeh,stonebig/bokeh,mindriot101/bokeh,dennisobrien/bokeh,bokeh/bokeh,mindriot101/bokeh,timsnyder/bokeh,dennisobrien/bokeh,jakirkham/bokeh,ericmjl/bokeh,jakirkham/bokeh,Karel-van-de-Plassche/bokeh,mindriot101/bokeh,timsnyder/bokeh,timsnyder/bokeh,bokeh/bokeh,Karel-van-de-Plassche/bokeh,dennisobrien/bokeh,philippjfr/bokeh,philippjfr/bokeh,Karel-van-de-Plassche/bokeh,rs2/bokeh,stonebig/bokeh,stonebig/bokeh,philippjfr/bokeh,bokeh/bokeh