Sslyze

* Fixed misc bugs introduced by the previous release (374, 375, 376).

* Major cleanup of `CertificateInfoPlugin` and `HttpHeadersPlugin`; the results returned by these plugins when using the Python API or the JSON or XML outputs have changed slightly, and should be easier to understand and use.
* However, existing code that parses these results will break.
* Fixed bug where SSLyze was unable to build the verified chain for a given server; OpenSSL is now used directly to build the verified chain (355).
* Fixed bug with IPv6 support (371).
* Fixed crash in the `RobotPlugin` (361).
* Converted the test suite to `pytest`.

* Updated [cryptography](https://cryptography.io/) module to 2.5.

* Various bug fixes (362)

* Various bug fixes (356, 357, 358).

* Bug fix for parsing Expect-CT headers.