Set font

def set_font(font, section='appearance', option='font'):
    """Set font"""
    CONF.set(section, option+'/family', to_text_string(font.family()))
    CONF.set(section, option+'/size', float(font.pointSize()))
    CONF.set(section, option+'/italic', int(font.italic()))
    CONF.set(section, option+'/bold', int(font.bold()))
    FONT_CACHE[(section, option)] = font