feat: can use escaped tokens inside quotes including quotes. Change tokenizer to support: cmd with arg "string with embedded \" double quote" works for single quotes too. Mixed quotes can skip the \" or \' escaping. Also: quoted cmds args "can include \n newline, \t tab and \r return" Added a doc example, also tests for new feature.

try:
    # Python 3+
    from ssl import SSLError
except (ImportError, AttributeError):
    # Python 2.5-2.7
    from socket import sslerror as SSLError  # noqa: F401