Feature request: to_glue

@ChrisBeaumont this is for you, maybe @astrofrog too since you made the successful one-off pvextractor widget.

Would it be possible to open a cube in Glue, or at least with the Glue quick-viewer, from within an existing session?  I'm thinking of getting access to on-the-fly coordinate changes within glue, essentially, but starting from a regular old command line application.
This will likely block until you close the UI, but should then return normally and finish the rest of the program. If you are running python and have executed "%gui qt", then it will run without blocking