Update emacsrunregion to display a finished message

emacsrunregion is used by matlab-sections.el and others. Emacs sends the emacsrunregion command to MATLAB and control is returned to Emacs. The emacsrunregion command run asynchronously, thus it would be good to have a completion message.

I added one in emacsrunregion, but it is currently commented out because we need to update the tests on unix to pass when this is activated.