Update to LPFTimeConstCalc notebooks

LPFConstCalc now does rising edge calculations and is formatted in an
easier to read format.
Creation of SomaPQuaCalc.nb

This document was originally adapted from SomaPTauCalc.nb, but
eventually used virtually none of the elements of SomaPTauCalc.nb b/c it
never automatically grabbed data from a file.  Instead, as a user, I
manually added values to the document and then used Mathematica to plot
the bifurcation line for a simulated neuron with identically-sized
transistors.  This is used to verify that the calibration process works
in a controlled, repeatable manner.