clean up confocal-scan.ipynb example notebook

[gadamc]

This example notebook contains a few unnecessary and confusing parts. In particular, using the "Namespace" object was a hack that shouldn't have been there.

Remove that and type out all of the arguments explicitly because that is simpler to read.

Then review the notebook to make sure it's clear what is happening.

[gadamc]

https://gist.github.com/gadamc/fe31b3504839cd0c62159cdb62e2d6b1