Let ana_scans fail when any command fails

[lmoureaux]

Description

Addresses #28

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Motivation and Context

Needed for unit testing, see #27 and #28

How Has This Been Tested?

Tested on Travis with --anaType=scurve. Worked fine both in case of success and in case of failure of the main analysis (output logs here (success), and here (analysis fails)).

Checklist:

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have added tests to cover my changes (not in this PR though).
• [x] All new and existing tests passed (not in this PR though).

[lmoureaux]

No, as I wouldn't be able to test it now that I'm gone.