The threshold for printing species is a new, optional parameter to the
'report' function. If any species are excluded, the total number of
minor species and their aggregate mass and mole fraction are printed.
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.
Visual Studio defaults to 3-digit exponents when printing in scientific
notation. The tests now use a MSVC-specific function to change this
behavior when necessary.
