Log Message:
v5.8.3
- Improve HTTP request line validation:
  * Improve HTTP version parsing
- Fix HTTP CONNECT method processing:
  * Respond with ``405 Method Not Allowed`` if ``proxy_mode is False``
  * Validate that request-target is in authority-form
- Improve tests in ``test.test_core``
- Fix EPROTOTYPE @ Mac OS

v5.8.2
- Fix 39 regression. Add HTTP request line check:
  absolute URI path must start with a
  forward slash ("/").