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]

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]

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, Daniel Bankhead, Daniel Stenberg, Gisle Vanem,
  Marcel Raad, Martin Storsjö, Max Dymond, moohoorama on github, Paul Howarth,
  Peter Piekarski, Ray Satiro, Rob Cotrone,
  (12 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