Omnibus release of dooooooooom

The list of changes in this release is long, and should serve as a warning to me to
make releases more often, as it cuts down on typing. Thanks to everyone who made
PRs, checked PRs, merged PRs, and... renewed PRs. Special thanks to Andrew Konchin
(@andrykonchin) who is responsible for over half the changes in this monster release,
and who has come on board as a maintainer.

This release removes the Rack::Runtime and Rack::Config middleware.
This may seem like a foolhardy thing to do in a minor release, but rack
itself ships with functionally identical versions. Compatibility
has been maintained by having require "rack/contrib/<thing>" still work, but
that should be changed to require "rack/<thing>" instead.

• A #close method was added to the body that is returned by Rack::Signals.

• A stub CHANGELOG.md, pointing to the canonical source of release notes, has
  been added.

• Thread safety issues in Rack::Access, Rack::CommonCookies, and Rack::Deflect
  have been fixed. Additionally, the need for a thread-safe external cache object in
  Rack::LazyConditionalGet has been documented.

• A SPEC violation in Rack::CSSHTTPRequest has been fixed.

• Case-sensitive header problems in a whole bunch of middlewares have been fixed.

• Rack::JSONBodyParser now only rescues JSON::ParserError if it is raised within
  the middleware's own code. Exceptions raised by the application itself will now
  be left alone to be handled elsewhere.

• All string literals are now frozen.

• Residual ye olde Ruby compatibility checks were removed from Rack::Backstage,
  Rack::MailExceptions and Rack::NestedParams.

• The length calculation in Rack::JSONP has been made simpler.

Stuck at home? Why not release your favourite collection of Rack contributions!

A healthy crop of fixes and new features in this release. Thanks to
everyone who contributed, and welcome to Andrew Konchin, as the newest
recipient of a commit bit.

• New middleware Rack::JSONBodyParser: a better-designed replacement for
  Rack::PostBodyContentTypeParser, with a more appropriate name (given
  that they both only handle JSON natively, having JSON in the name seems
  like a good idea), and with a better set of default behaviours and knobs.
  It is also significantly faster than PostBodyContentTypeParser.

• Rack::PostBodyContentTypeParser: this middleware's interface is a
  bit of a mess, which makes it nearly impossible to improve in a
  backwards-compatible manner. As a result, its use has been deprecated, in
  favour of Rack::JSONBodyParser.

• Several middlewares that set Content-Length headers were fixed to use
  String#bytesize, instead of String#size, which makes multibyte characters
  much happier. (Chris Frank)

• Rack::ResponseCache: Make header detection case-insensitive. (Chris Frank)

• A lot of broken tests and deprecation warnings in the test suite were
  fixed. (Andrew Konchin)

• Rack::Locale: significant correctness fixes, including q=0 handling,
  case insensitivity where appropriate, and better handling of whitespace.
  (Andrew Konchin)

• Rack::StaticCache: several correctness fixes, such as setting a Date
  response header, use UTC in timestamps, and improving the robustness of
  the date rendering.

Share and enjoy!

Spring has sprung so let's make a new release

New features:

• Rack::PostBodyContentTypeParser -- you can now pass a block to the
  middleware to override the default "parse me some JSON" behaviour. Thanks
  to Kris Dekeyser (@Kris-LEBIS) for the patch.

• Ruby 2.5 support -- we're now running the test suite through Ruby
  2.5.1, as well as the latest patch releases of all other Ruby releases
  supported by rack-contrib (back to 2.2, the same as Rack itself). The
  only "interesting" change here is that some Rack::Profiler printers no
  longer work, which is not our fault, but rather a problem with
  ruby-prof.

Bug fixes:

• Remove a deprecation warning about has_rdoc. Thanks to Luciano Sousa
  (@lucianosousa) for the patch.

Multibytes bytes again!

This is a bugfix release, which fixes a Rack 2 incompatibility in
Rack::NotFound, where the wrong value for the Content-Length response
header was calculated (#143).

Thanks to Kazuhiro NISHIYAMA (@znz) for the bug report, and Joe Francis
(@lostapathy) for the fix.

Rack 2.x Support Is HERE!

Thanks to the hard work of Skye Shaw, amongst others, this release of
rack-contrib supports Rack 2.x. Unfortunately, it only supports Rack
2.x; if your application is using Rack 1.x, you should continue to use
rack-contrib 1.x.

The non-backwards-compatible, user-visible changes are:

• Drop support for Ruby versions less than 2.2. Rack 2 does not support
  these older releases, so there's no benefit in our doing so.

• Rack::NestedParams: switch to using Rack::Utils.parse_nested_query to
  parse request bodies, which handles repeated element keys differently.
  See #92.

• Rack::Sendfile: removed completely. Rack core provides a middleware of
  the same name that is much better, and more actively maintained, and you
  should use that instead.

• Rack::AcceptFormat: removed completely, because it is terribad.

End of an era: support ending for Rack 1.x

This is intended to be the final release of rack-contrib with support for
the Rack 1.x series. Deprecations have been added for the
non-backwards-compatible changes, so you can get a sense of what will need
to be fixed.

Regular changes in this release:

• Rack::Locale: use a default locale (specified by I18n.default_locale = :<something>) if no available locale matches the Accept header.
  (Hiroki Yoshioka)

• Our test suite is now minitest 6 compliant, since all deprecation warnings
  have been cleaned up. (Skye Shaw)

Deprecation warnings added:

• Rack::Sendfile is gone, because there's a better one in Rack itself. If
  your code loads rack/contrib/sendfile, you'll get a warning.

• Rack::NestedParams behaviour has changed if multiple instances of the same
  variable are found in a query string (foo=1&foo=2 currently evaluates to
  foo=1; it will evaluate to foo=2 in rack-contrib 2.x). This is
  necessary because we're using Rack's built-in query string parsing rather
  than our own rather ugly implementation. If you hit the changed
  behaviour, you'll get a warning. (Skye Shaw)

• Rack::AcceptFormat -- whilst this has been deprecated for a while, it's
  worth reiterating that if you're still using this thing, you should really
  stop. It's sooooo bad.

October: catastrophe avoidance month

• Rack::JSONP: change the callback validity checking regex to one
  that isn't vulnerable to catastrophic backtracking, which causes all sorts
  of nasty performance problems when there's a long invalid string to match
  against. PR by Juan C.
  Muller (@jcmuller).

September is the season of correct error handling

• Rack::PostBodyContentTypeParser: if the middleware is told a POST
  body is JSON, but it doesn't parse as JSON, then... it's not really JSON,
  and the request is now rejected with a 400 response. Thanks to Yukihiko
  SAWANOBORI (@sawanoboly) for the fix.

We're baaaaaaack!

After an extended hiatus, rack-contrib maintenance is back on track. This
is a tidy-up release, merging things that have sat around for far too long.

• git-version-bump has now been moved to being a development dependency,
  thanks to Tobias Haagen Michaelsen.

• Rack::AcceptLocale can be restricted to a set of enforced locales, thanks
  to Paco Guzman.

• Rack::NotFound's path argument is now optional, thanks to Ed Morley.

• Rack::BounceFavicon now has a description and tests, thanks to Steven
  Wilkin.

• The automated Travis CI suite now tests all supported Ruby versions up to
  2.4, which necessitated a few small changes.

v1.4.0: Features, Features Everywhere, and not a bug to fix

There's a bumper crop of new features this month. Share and enjoy!

Deprecations

• Rack::AcceptFormat is slated for removal in rack-contrib 2.0.0 (due
  on or after 1 January, 2016. Using this middleware will now result in a
  deprecation warning being printed to stderr. If you use this
  middleware, now would be a good time to start doing things properly.

Features

• Rack::LazyConditionalGet: new middleware, by
  Mig. This middleware tracks when the last
  POST/PUT/DELETE request was made, and returns 304 responses to requests
  which include a Last-Modified entity request header which is greater
  than or equal to that time.
• Rack::StaticCache: You can now specify a custom "version" regex for your
  cache invalidation, if the default doesn't do it for you. Initial patch
  provided by Eric Boehs.
• Rack::Profiler: You can now run a single request through the profiler
  multiple times, by adding the profiler_runs query parameter to the URL.
  Patch provided by Bryce McDonnell.