Added the Schwartz & smith model port.

The code was ported from the work of Moeti Ncube available here: http://www.mathworks.com/matlabcentral/fileexchange/29751-calibration-method-for-the-schwartz-smith-model
Right now it's just a simple direct port of the code and still lacks the needed clean up and conversion to plug-in for Fairmat.
Updated the README.