Add regress coverage for tls_peer_cert_common_name()

Adjust tls regress for protocol parsing fixes

This mostly reverts what was done by beck in Tallinn and adjust tlstest
to add new test cases and now failing connection tests.

Remove the ability to do tls 1.0 and 1.1 from libtls.

With this change any requests from configurations to request
versions of tls before tls 1.2 will use tls 1.2. This prepares
us to deprecate tls

Remove the ability to do tls 1.0 and 1.1 from libtls.

With this change any requests from configurations to request
versions of tls before tls 1.2 will use tls 1.2. This prepares
us to deprecate tls 1.0 and tls 1.1 support from libssl.

ok tb@

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Update protocol version test to include TLSv1.3.

Add tls_conn_cipher_strength() to gotls regress.

Fix a format string issue that Go 1.10 complains about.

Improve unknown protocol version handling.

In ssl.h TLS 1.0 is called TLSv1. Adapt name in test to make it pass.
OK jsing@

Allow ciphers to be set on the TLS config.

Provide support for libtls protocols and allow for protocols to be set on
a TLS config. The ConnVersion function now also returns a protocol version
instead of a string.

Add handling for errors on the TLS config and properly check/handle
failures when setting the CA file.

libtls errors are much more descriptive these days - return them directly
and avoid adding redundant/duplicate information.

We no longer need to keep pointers following tls_config_set_*() calls.

Add test coverage for peer certificate info and connection info.

Make regress work again post hackathon tls_handshake/tls_read/tls_write
changes.

Update for recent verify related naming changes.

Update regress for the libressl to libtls rename.