Add proper dialog for plotly export

[astrofrog]

This supports selecting the sharing privileges, and the account to export to:

This still needs:

• Changelog
• Tests
• Remove 'enter a label' dialog

[sbussmann]

That looks good to me. Is the username automatically detected and displayed in the pop-up dialog? Or do all users just get astrofrog as an example username?

Also, there's typo: "Plotly usng secret URLs..." --> "Plotly using secret URLs"

[astrofrog]

That looks good to me. Is the username automatically detected and displayed in the pop-up dialog? Or do all users just get astrofrog as an example username?

It loads the username from the .plotly/.credentials file if present

Thanks for spotting the typo! Currently working on the tests and will fix that at the same time.

[sbussmann]

Ok, looks good to me! Nice work!

[astrofrog]

@sbussmann - this is now merged - let me know if you try it out at some point. This will be included in the 0.9.0 release which is a few weeks away, but you can use the developer version of glue in the mean time.