Considering underflow bin in magnetic field mapper helper function (was ACTS-419)

Original author Julia Hrdinka @jhrdinka

Since the implementation of the Acts::Grid is designed using the first bin as an underflow bin, filling the magnetic field map needs to begin at 1( not at 0 ), in the helper function to create a magnetic field mapper.

Edited Mar 27, 2019 by Moritz Kiehn

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