There are a series of activity coefficients for published battery models
which actually overflows. Cantera was treating this as a nonerror and changing
the return results without comment. This is not correct. Made the behavior a
user controlled capability.
CanteraError inerits from std:exception, so now it has a what() method
that is used to print a message describing the exception. Adding an
exception to the Cantera error stack now requires explicitly calling
the .save() method.