This commit expands the range of whitelisted extensions by checking
if an extension can be resolved to image/*, audo/*, video/*, as well
as any content type that ends with +xml.

Issue: SPR-13643

We know skip the Content-Disposition header for any extension if the
chosen request mapping explicitly contains the URl extension.

Issue: SPR-13629

Prior to this change, the HttpEntityMethodProcessor would try to process
conditional requests that are undefined by the spec, such as:

* an HTTP GET request with "If-None-Match:*"
* a request with both "If-None-Match" and "If-Match"
* a request with both "If-None-Match" and "If-Unmodified-Since"

This commit skips the processing of those requests as conditional
requests and continues with normal request handling.

Issue: SPR-13626

Issue: SPR-13530

Issue: SPR-13531

Issue: SPR-13642

Issue: SPR-13643

Issue: SPR-13621

Issue: SPR-13621

The URI template is now manually parsed vs using a regex to extract
URI variable names and to create a pattern for matching to actual URLs.
This provides more control to deal with nested curly braces.

Issue: SPR-13627

Issue: SPR-13621

AnnotatedElementUtils consistently operates on actual annotation type if available (for performance reasons)

The goal is to avoid String name comparisons in favor of annotation type identity checks wherever possible. Also, we avoid double getDeclaredAnnotations/getAnnotations checks on anything other than Classes now, since we'd just get the same result in a fresh array.

Issue: SPR-13621

Issue: SPR-13621

Improve the performance of the `getMergedAnnotationAttributes` and
`isAnnotated` methods in `AnnotatedElementUtils` by returning
immediately when the element had no annotations.

Issue: SPR-13621

Issue: SPR-13621

Add new MediaType.APPLICATION_JSON_UTF8 and
MediaType.APPLICATION_JSON_UTF8_VALUE constants for
"application/json;charset=UTF-8" content type in order to make it
easier to override @RequestMapping "produces" attribute without
losing the default JSON charset (UTF-8).

Issue: SPR-13600

Issue: SPR-13621

Issue: SPR-13634

Issue: SPR-13633

Issue: SPR-13629

Issue: SPR-13633

Issue: SPR-13628

Issue: SPR-13611

Issue: SPR-13596

Issue: SPR-13600

* pr/908:
  Fix typo

Closes gh-908

Refine the approach of having <mvc:view-resolvers> detect and use the
ContentNegotiationManager instance registered with
<mvc:annotation-driven> introduced in the last commit.

Issue: SPR-13559

The <mvc:annotation-driven> element now adds an alias when a
ContentNegotiationManager bean is registered with a custom name.
This helps <mvc:view-resolvers> to more reliably find such a custom
ContentNegotiationManager.

Issue: SPR-13559

Issue: SPR-13234

Issue: SPR-13607

Prior to this change, serving resources with ResourceHttpRequestHandler
could result in NPE when requesting an existing folder located in a JAR.

This commit swallows those exceptions, as it is not possible to foresee
those cases without reading the actual resource. This result in a HTTP
200 response with a zero Content-Length instead of a HTTP 500 internal
exception.

Issue: SPR-13620

Issue: SPR-13615