Localization of differentials works.

We can now correctly, stably, and quickly compute localizations of
differentials at places. The instability was caused by the division of
large magnitude numbers. Therefore, a Taylor series expansion of the
differential centered at a place is computed.

What remains is the addition of a new path type for going to
discriminant places. In order to make the mathematics cleaner for
integration of holomorphic differentials it may be beneficial to use a
path determined by the x-part of the target place.