Added support for optional TLS commands BIO_CTRL_POP and BIO_CTRL_PUSH.
BIO_CTRL_PUSH is an optional value that is not handled in the tlsBIO:BioCtrl().

The larger problem is that the library does not support new optional commands because it returns -2 for unknown cmds in BioCtrl(). I would suggest changing the default return value to 0. I confirmed that this fixed the issue.

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