Update mean H, E, Z, F function in ObservationBaselineCalculator to only use 4 values from the correct measurements
Fix merge conflict, use version with less than 80 character lines
Refactor to use to.be.closeTo instead of EPSILON constant
Replace instances of getMeanValue with meanH, meanE, meanZ, meanF where appropriate
Clean up and refactor code
Merge branch 'ObservationBaselineFixesPartDux' of https://github.com/emcwhirter-usgs/geomag-baseline-calculator into emcwhirter-usgs-ObservationBaselineFixesPartDux