Add more format support like *args #220

def gettext(string, *args, **variables):
    """
        gettext(u'Hello World!')
        gettext(u'Hello %(name)s!', name='World')
        gettext(u'Hello %s!', 'World')
    """
    t = get_translations()
    if t is None:
        return string if not variables else string % variables
    s = t.ugettext(string)
    if args:
        return s % args
    else:
        return s if not variables else s % variables