'This method sets the font size roughly in points. A size of 10 is almost
too small to read. A size of 20 is roughly 10 pixels high and a good choice.
Parameters:
sz = Int'

def setFontSize(self, sz):

    self._mFontSize = sz
    self._mFont = pg.font.Font(self._mFontName, self._mFontSize)
    return None
