Version 2.0.0 Alpha 4

This is an update for the version 2.0.0 work in progress.

Significant work has been in progress on the HTTP framework, and there are breaking API changes.
The docs have gotten more love.

And thanks to @shikokuchuo we have a fix for the long standing Windows IPC hang!

What's Changed

• http test: test HEAD method in server by @gdamore in #2078
• Http no tree exclusive by @gdamore in #2079
• Http no res req by @gdamore in #2080
• Status fix by @gdamore in #2081
• http: use common canonify at request parse time by @gdamore in #2082
• http: server error handling improvements and tests by @gdamore in #2083
• http: fix mishandling of very long headers or URIs, and mishandling o… by @gdamore in #2084
• Http nng err by @gdamore in #2085
• Pipe docs by @gdamore in #2086
• Docs updates by @gdamore in #2087
• http docs: documentation conversion for http handlers by @gdamore in #2088
• fixes #2092 nng_close may hang on Windows by @gdamore in #2095

Full Changelog: v2.0.0-alpha.3...v2.0.0-alpha.4