PsychHID: Update code comment wrt. CTRL+C handling on Octave 3.8

Update April 2014: As of Octave 3.8.1 on Linux, sending SIGINT
explicitely when running under Octave 3.8 with QT based GUI is no
longer needed for the Qt-GUI, and also not executed, because GNUTERM
is no longer set to 'qt', so all is good :)