Update MATLAB documentation

Hey Ray,

Here's my updated commits for updating the MATLAB documentation and small changes to the interface. If these changes look good to you, I'll send them to the SVN.

I emailed Harry again to add me to the Cantera-dev group to check there on whether to rename the toolbox as we discussed in the last pull request. For a big change like that that might break things, I was thinking it would be better to get more opinions. Could you let me know whether this is likely to get a favorable response?

Best,
Bryan