For entries that are lists of maps in the general case but often only contain
one item, it is convenient to allow them to be provided as just a map. This
modifies methods used to work with vectors of AnyMap objects to handle the
case where the child object is just a map.

…ions

This allows for error checking at the time of adding the alias, as well as
providing a public interface for adding aliases.

The first phase in a Kinetics object is not necessarily the reacting phase
for Kinetics objects loaded from CTI/XML files, but is for YAML files.

Ensure that the name returned by Sub::name() is a name that can be used to
reconstruct a substance of the same type.

Make phase names in liquidvapor.yaml match the substance model names.

After calculating properties using finite differences (e.g. cp), the fluid was
returned to its original state by setting the state in terms of pressure and
temperature. However, because setting the state using these variables is an
iterative calculation with some error tolerance, the state was not restored
exactly. By restoring the state based on the initial temperature and density,
the restored state is identical to the initial state.