autobahn websocket test suite tracking

To ensure that actix-web provides production-grade websockets, it should pass the crossbar autobahn test suite.

https://github.com/crossbario/autobahn-testsuite

Currently failing cases:

• 3.1 - Issue #1579, PR #xx
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 5.3–5.8 - fixed in https://github.com/actix/examples/commit/561d76830413e906f19944ad78fceddde37cc889
• 5.18 - fixed by #4219
• 5.19—5.20 - fixed in https://github.com/actix/examples/commit/561d76830413e906f19944ad78fceddde37cc889
• 6.1.2—6.1.3 - fixed in https://github.com/actix/examples/commit/561d76830413e906f19944ad78fceddde37cc889
• 6.2.2—6.2.4 - fixed in https://github.com/actix/examples/commit/561d76830413e906f19944ad78fceddde37cc889
• 6.3.2 - fixed in https://github.com/actix/examples/commit/561d76830413e906f19944ad78fceddde37cc889
• 6.4.1
• 6.4.2
• 6.4.3
• 6.4.4
• 7.1.3—7.1.4 - user dependent: closed in actix/examples#335
• 7.9.1–7.9.9 - fixed by #4218
• 9.x.x - fixed in https://github.com/actix/examples/commit/36d5d4f18896be9732bf937ceadc2be552589906
• 10.1.1 - fixed in https://github.com/actix/examples/commit/561d76830413e906f19944ad78fceddde37cc889