Add Puiseux extension to given point.

PuiseuxTSeries.extend_to_t() will in-place compute the
number of terms needed for the Puiseux series to approximate
the curve at a provided t-value to a given accuracy. (With
a default of 1e-8.) This is especially useful for Puiseux-
based analytic continuators.
Checkpoint: pre-discriminant points refactor.
Resolved pre-initialization RSP bug.

There was a bug where RSPs and ACs were trying to call
the PathFactory object before it was fully initialized.
This bug is now resolved.