Initial pass at implementing Maskell solid solution ThermoPhase.

Based on Maskell, Shaw, and Tye, Electrochimica Acta 28(2) 225-230 1983.
Includes unit tests checking calculation of the chemical potential values
and parsing of the mixing enthalpy parameter from an XML file.



git-svn-id: https://cantera.googlecode.com/svn/cantera/trunk@2772 02a645c2-efd0-11dd-984d-ab748d24aa7e
Fix linker error when using MSVC

Regression was introduced in r2755.

git-svn-id: https://cantera.googlecode.com/svn/cantera/trunk@2773 02a645c2-efd0-11dd-984d-ab748d24aa7e