FM1DElectroStatic, FM1DElectroStatic_fast, FM1DMagnetoStatic and FM1DMagnetoStatic_fast.

The first bug had to do with field normalization. Although the 1D field profile
derivatives were normalized properly, the actual field was not. Instead of
looping through all of the field values, the loop was over the Fourier 
accuracy parameter. This typically had the effect that the on axis field was not
normalized at all. For input fields that were already normalized to 1, this
had no effect. However, if the input field was not then the field expansion
was incorrect.

The second had to do with the Fourier expansion used to calculate the 
derivatives of the on axis field. The code reflects the input
field in order to ensure that it is periodic. For best accuracy, this 
reflection should be about the first point of the input data (z = 0). However,
what was actually implemented was a reflection about -delta / 2, where delta
is the 1D grid spacing. This caused an error that was small, and became
smaller with decreasing delta, but significant. Using the new implementation,
the reconstruction of the field file for the Envelope-Tracker-Phase-1
(FINSS-RGUN.dat) is about two orders of magnitude more accurate than when
using the old Fourier expansion implementation. Even though this error was
small, there was a noticeable difference in the beam envelope when running
the Envelope-Tracker-Phase-1 and ExternalFieldTest regression tests. The
reference files for both of the tests were updated using the new field
classes.

A quick glance shows that the Fourier expansion bug may also be present in the
1D Astra field classes, but I need to look more carefully to be sure.

Finally, all six classes were cleaned up to conform to the new coding style.