Robust exception handling

[pwolfram]

The analysis framework should be fault-tolerant to a variety of error situations. For example, when a data set or input file is missing, or an analysis is misconfigured. Individual processes should be allowed to "error out" without halting the system.

[milenaveneziani]

This issue is similar to the modularity thing: it is going to be on-going as the analysis evolves. I would suggest to close it, and we will have specific issues about this in the (very) near future.

[pwolfram]

Sounds good @milenaveneziani, we have an issue #58 to help address this and are on the lookout to do better exception handling so I'm going to close this for now. Please reopen if needed.