Fix infinite loop against servers that respond with invalid cipher IDs

Updated man page to include new summary and new TLS v1.3 options.

Now prints the curve name and key strength for ECC certificates.

Update readme to remove note about OpenSSL v1.1.0.

Removed unnecessary warning about SSLv2 not being supported by OpenSSL

Fixed docker tests

Allow trailing slash ('/') in URLs with no port specified

Using a URL with a trailing slash, and not specifying a port, results in the slash being added to the host string and causing a resolution failure.
The fix is adding checks to truncate the trailing slash in the same way a colon would be during port specification.

However, the way this handles `/` and `:` interchangeably at the end means that the URL `https://example.org/4443/` is parsed the same as `https://example.org:4443/`.

Enumerate signature algorithms for TLSv1.2 and below