Parse in a command line string which may be quoted.

def parse_cmd_string(text, off, trim=True):
    '''
    Parse in a command line string which may be quoted.
    '''
    if trim:
        _, off = nom(text, off, whites)

    if isquote(text, off):
        return parse_string(text, off, trim=trim)

    if nextchar(text, off, '('):
        return parse_list(text, off)

    return meh(text, off, whites)