Provide intuitive explanatory messages for errors in Notebook components

[evmorfia-b]

We should provide more/better feedback to the user when something is not working properly, both when the user does sth unexpected (e.g. apply a filter that doesn't make sense) and when the tools face other internal issues.

[pitsios-s]

Removed 'UBITECH' tag from this issue, since exception handling for the visualizer was addressed in #60.