bugfix for fuselage VD to account for non-zero origin fuselage

[rachealerhard]

Pull Request Checklist

• Merge in the latest Develop branch changes to your branch
• Remove .pyc files from your repository:
  • Linux/Mac
    • find . -name *.pyc -delete
  • Windows
    • del /S *.pyc
• Run automatic regression and makes sure everything is passing
• Did you make a new regression test that covers your new code?
• Did you update your docstrings?
• Did you update your headers to include your name and date?
• Do a final compare with the Develop branch to be sure what you're changing

[coveralls]

Coverage: 90.281% (+0.0006%) from 90.28% when pulling 4aaba5f on fix-fuselage_vortex_distribution into f551a68 on develop.