Merge pull request #219 from mozmark/20200214-4-0-0

rename 3.3.0a7 to 4.0.0 because of breaking changes

TLS Canary experimental release: 3.3.0a1

TLS Canary hotfix release 3.2.2

TLS Canary latest stable release: 3.2.2

TLS Canary hotfix release 3.2.1

TLS Canary feature release 3.2.0

TLS Canary bugfix release 3.1.2

TLS Canary v3.1.1 Hotfix-Release

What's new?

* TLS Canary is now a proper Python package. Stable releases can be installed with a simple `pip install tlscanary`.
* Command line now takes "run modes" as first positional argument. Intrnally the argument parser employs subparsers for this, thus shared arguments like `--workdir` and `--debug` must now be given before the run mode argument.
* Run modes `performance`, `regression`, and `scan` now log into a central logging facility that stores compressed run logs in `~/.tlscanary/log`. Producing a report now requires a separate call to `tlscanary`. To generate the legacy HTML report, use a variation of `tlscanary log -a htmlreport`.
* Introduced a new run mode called `log` for maintaining the run log database and generating reports. See `tlscanary log --help` for details.
* The `-t/--test` and `-b/--base` now also take paths to Firefox package files or build trees.
* Introduced a new JSON-based log format, produced by `tlscanary log -a json`.
* Much more metadata is collected about the test candidates.
* You can now set prefs in the test candidates using the `-p/-p1/p2` arguments, just like in good old *ssl_canary* days.
* Windows PowerShell is now a fully supported platform.
* Introduced a `srcupdate` run mode for updating host databases. See `tlscanary srcupdate --help` and the [README](README.md) for details.
* Scans are temporarily limited to 100k hosts per default. This hotfix was introduced to work around instabilities on some machines that do not have sufficient amount of swap memory.
* Introduced several internal architecture changes that made all those new features possible.

Bugfix release for upstream changes in OneCRL tools