Fix demo examples

[erentar]

demo.ipynb had some wrong elements, i correct these discrepancies in this pr.

[fabricebrito]

Thanks for this and sorry for the painful debugging experience. This project was created for a version of SNAP back in the days.
I've reached out to ESA a few times to understand the future of this project but got no feedback. At some point I got the feeling it would be integrated in the SNAP project but it never happened.
Its maintenance is thus low priority as we have other open source priorities.

[erentar]

I did not mean to berate the project by saying "many hours of debugging", all i wish to is to prevent others the same troubleshooting by giving a correct example

Thank you for your efforts in building this project, it is helping me a lot at the moment

[fabricebrito]

@erentar looking at the PR I guess the changes are related to SNAP 9 (or 10, don't know) while the original demo is based on SNAP 8

Operators interfaces may change between SNAP releases and this is why snapista is "dynamic"

I guess the way forward is to split the demo notebooks into SNAP version based.

I'll try to find time to work this out.

Thanks for your feedback and efforts. Sorry for your initial frustration :-)