Curl and libcurl 7.57.0

 Public curl releases:         171
 Command line options:         211
 curl_easy_setopt() options:   249
 Public functions in libcurl:  74
 Contributors:                 1626

This release includes the following changes:

 o auth: add support for RFC7616 - HTTP Digest access authentication [12]
 o share: add support for sharing the connection cache [31]
 o HTTP: implement Brotli content encoding [28]

This release includes the following bugfixes:

 o curl_mime_filedata.3: fix typos [1]
 o libtest: Add required test libraries for lib1552 and lib1553 [2]
 o fix time diffs for systems using unsigned time_t [3]
 o ftplistparser: memory leak fix: free temporary memory always [4]
 o multi: allow table handle sizes to be overridden [5]
 o wildcards: don't use with non-supported protocols [6]
 o curl_fnmatch: return error on illegal wildcard pattern [7]
 o transfer: Fix chunked-encoding upload too early exit [8]
 o curl_setup: Improve detection of CURL_WINDOWS_APP [9]
 o resolvers: only include anything if needed [10]
 o setopt: fix CURLOPT_SSH_AUTH_TYPES option read
 o appveyor: add a win32 build
 o Curl_timeleft: change return type to timediff_t [11]
 o cmake: Export libcurl and curl targets to use by other cmake projects [13]
 o curl: in -F option arg, comma is a delimiter for files only [14]
 o curl: improved ";type=" handling in -F option arguments
 o timeval: use mach_absolute_time() on MacOS [15]
 o curlx: the timeval functions are no longer provided as curlx_* [16]
 o mkhelp.pl: do not generate comment with current date [17]
 o memdebug: use send/recv signature for curl_dosend/curl_dorecv [18]
 o cookie: avoid NULL dereference [19]
 o url: fix CURLOPT_POSTFIELDSIZE arg value check to allow -1 [20]
 o include: remove conncache.h inclusion from where its not needed
 o CURLOPT_MAXREDIRS: allow -1 as a value [21]
 o tests: Fixed torture tests on tests 556 and 650
 o http2: Fixed OOM handling in upgrade request
 o url: fix CURLOPT_DNS_CACHE_TIMEOUT arg value check to allow -1
 o CURLOPT_INFILESIZE: accept -1 [22]
 o curl: pass through [] in URLs instead of calling globbing error [23]
 o curl: speed up handling of many URLs [24]
 o ntlm: avoid malloc(0) for zero length passwords [25]
 o url: remove faulty arg value check from CURLOPT_SSH_AUTH_TYPES [26]
 o HTTP: support multiple Content-Encodings [27]
 o travis: add a job with brotli enabled
 o url: remove unncessary NULL-check
 o fnmatch: remove dead code
 o connect: store IPv6 connection status after valid connection [29]
 o imap: deal with commands case insensitively [30]
 o --interface: add support for Linux VRF [32]
 o content_encoding: fix inflate_stream for no bytes available [33]

This release includes the following known bugs:

 o see docs/KNOWN_BUGS (https://curl.haxx.se/docs/knownbugs.html)

This release would not have looked like this without help, code, reports and
advice from friends like these:

  Alessandro Ghedini, Andrew Lambert, arainchik on github, cbartl on github,
  Dan Fandrich, Daniel Bankhead, Daniel Stenberg, Dmitri Tikhonov, Gisle Vanem,
  Jakub Zakrzewski, Juro Bystricky, Luca Boccassi, Marcel Raad, Martin Storsjö,
  Max Dymond, moohoorama on github, omau on github, Patrick Monnerat,
  Paul Howarth, Pavel Gushchin, Per Lundberg, Peter Piekarski, Petr Voytsik,
  Ray Satiro, Rob Cotrone, Viktor Szakáts,
  (26 contributors)

        Thanks! (and sorry if I forgot to mention someone)

References to bug reports and discussions on issues:

 [1] = https://curl.haxx.se/bug/?i=2008
 [2] = https://curl.haxx.se/bug/?i=2006
 [3] = https://curl.haxx.se/bug/?i=2004
 [4] = https://curl.haxx.se/bug/?i=2013
 [5] = https://curl.haxx.se/bug/?i=1982
 [6] = https://curl.haxx.se/bug/?i=2016
 [7] = https://curl.haxx.se/bug/?i=2015
 [8] = https://curl.haxx.se/bug/?i=2001
 [9] = https://curl.haxx.se/bug/?i=2025
 [10] = https://curl.haxx.se/bug/?i=2023
 [11] = https://curl.haxx.se/bug/?i=2021
 [12] = https://curl.haxx.se/bug/?i=1934
 [13] = https://curl.haxx.se/bug/?i=1879
 [14] = https://curl.haxx.se/bug/?i=2022
 [15] = https://curl.haxx.se/bug/?i=2033
 [16] = https://curl.haxx.se/bug/?i=2034
 [17] = https://curl.haxx.se/bug/?i=2026
 [18] = https://curl.haxx.se/bug/?i=2031
 [19] = https://curl.haxx.se/bug/?i=2032
 [20] = https://curl.haxx.se/mail/lib-2017-11/0000.html
 [21] = https://curl.haxx.se/bug/?i=2038
 [22] = https://curl.haxx.se/bug/?i=2047
 [23] = https://curl.haxx.se/bug/?i=2044
 [24] = https://curl.haxx.se/bug/?i=1959
 [25] = https://curl.haxx.se/bug/?i=2054
 [26] = https://github.com/curl/curl/commit/f121575#commitcomment-25347120
 [27] = https://curl.haxx.se/bug/?i=2002
 [28] = https://curl.haxx.se/bug/?i=2045
 [29] = https://curl.haxx.se/bug/?i=2053
 [30] = https://curl.haxx.se/bug/?i=2061
 [31] = https://curl.haxx.se/bug/?i=2043
 [32] = https://curl.haxx.se/bug/?i=2024
 [33] = https://curl.haxx.se/bug/?i=2060