Reported-by: Aron Bergman
Bug: https://curl.haxx.se/mail/lib-2018-03/0049.html

[ci skip]

... so that the CI and more detects compiler warnings/errors properly!

Closes #2337

Fixes #2342

Detected using the `codespell` tool.

Also contains one URL protocol upgrade.

Closes https://github.com/curl/curl/pull/2334

- Add new option CURLOPT_RESOLVER_START_FUNCTION to set a callback that
  will be called every time before a new resolve request is started
  (ie before a host is resolved) with a pointer to backend-specific
  resolver data. Currently this is only useful for ares.

- Add new option CURLOPT_RESOLVER_START_DATA to set a user pointer to
  pass to the resolver start callback.

Closes https://github.com/curl/curl/pull/2311

- In keeping with the naming of our other connect timeout options rename
  CURLOPT_HAPPY_EYEBALLS_TIMEOUT to CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS.

This change adds the _MS suffix since the option expects milliseconds.
This is more intuitive for our users since other connect timeout options
that expect milliseconds use _MS such as CURLOPT_TIMEOUT_MS,
CURLOPT_CONNECTTIMEOUT_MS, CURLOPT_ACCEPTTIMEOUT_MS.

The tool option already uses an -ms suffix, --happy-eyeballs-timeout-ms.

Follow-up to 2427d94c which added the lib and tool option yesterday.

Ref: https://github.com/curl/curl/pull/2260

- Add new option CURLOPT_HAPPY_EYEBALLS_TIMEOUT to set libcurl's happy
  eyeball timeout value.

- Add new optval macro CURL_HET_DEFAULT to represent the default happy
  eyeballs timeout value (currently 200 ms).

- Add new tool option --happy-eyeballs-timeout-ms to expose
  CURLOPT_HAPPY_EYEBALLS_TIMEOUT. The -ms suffix is used because the
  other -timeout options in the tool expect seconds not milliseconds.

Closes https://github.com/curl/curl/pull/2260

This enables users to preresolve but still take advantage of happy
eyeballs and trying multiple addresses if some are not connecting.

Ref: https://github.com/curl/curl/pull/2260

URL: https://curl.haxx.se/mail/lib-2018-02/0072.html

removed SSLKEYLOGFILE support (fixed)

removed "consider SSL patches" (outdated)

Closes #2310

Reported-by: Erik Johansson
Bug: https://github.com/curl/curl/commit/d9392268131c1b8d18dec3fa30e0bded833a5db7#commitcomment-27607495

Also expanded the CURL_REFUSE_CLEARTEXT section with more ideas.

This reverts commit de9fac00.

Reported-by: Jay Satiro

Closes #1603

Closes #1254

Closes #2302

Reported-by: Klaus Stein

... just to make it more apparent. Even if it repeats
some pieces of information.

Mentioned-By: Rich Moore

To make more accessible.

Merged in some new language from "URLs are dangerous things" as discussed on
the mailing list a few days ago:

Bug: https://curl.haxx.se/mail/lib-2018-02/0013.html

Bug: https://bugzilla.redhat.com/1542256

Closes #2306