Possibility to include np.inf as end point in pd.cut bins.

[mattias-lundell]

I don't know if it is desirable, but I think it would be nice to be able to include an infinity value as the endpoint to the bins in pandas cut function.

pd.cut([10, 20], [1, 5, np.inf], right=False)

[filmor]

Actually this is possible, however the _format_labels function tile.py has to be fixed to properly display inf values. If you define the labels manually it works.

[jreback]

@filmor want to do a PR for this?

[jreback]

closed by #4954