This commit introduces support for attribute overrides for
@ResponseStatus when @ResponseStatus is used as a meta-annotation on
a custom composed annotation.

Specifically, this commit migrates all code that looks up
@ResponseStatus from using AnnotationUtils.findAnnotation() to using
AnnotatedElementUtils.findMergedAnnotation().

Issue: SPR-13441

This split avoids a package tangle (between core and core.annotation) and also allows for selective use of raw annotation exposure versus synthesized annotations, with the latter primarily applicable to web and message handler processing at this point.

Issue: SPR-13153

Issue: SPR-11393

Issue: SPR-12926

Fix remaining Java compiler warnings, mainly around missing
generics or deprecated code.

Also add the `-Werror` compiler option to ensure that any future
warnings will fail the build.

Issue: SPR-11064

Remove Javadoc linkplain to ExceptionHandler#value() from
AnnotationMethodHandlerExceptionResolver to work around JDK
Javadoc bug 9007707.

Issue: SPR-10130

This reverts commit 45fa5082, reversing
changes made to a312d900.

Issue: SPR-10130

Issue: SPR-10128

In particular, avoiding synchronized Sets and Maps wherever possible (preferring a ConcurrentHashMap even instead of a synchronized Set) and specifying appropriate ConcurrentHashMap initial capacities (even if we end up choosing 16).

Issue: SPR-10005

Caching of resovled exceptions introduced in SPR-7703 also introduced a
side effect whereby if exactly one exception was previously cached, any
other exception would appear as a match to the previously matched
@ExceptionHandler method.

This change ensures use of a fresh map when determining matching
@ExceptionHandler methods while also updating the cache.

Issue: SPR-9209

Issues: SPR-9138

This renaming more intuitively expresses the relationship between
subprojects and the JAR artifacts they produce.

Tracking history across these renames is possible, but it requires
use of the --follow flag to `git log`, for example

    $ git log spring-aop/src/main/java/org/springframework/aop/Advisor.java

will show history up until the renaming event, where

    $ git log --follow spring-aop/src/main/java/org/springframework/aop/Advisor.java

will show history for all changes to the file, before and after the
renaming.

See http://chrisbeams.com/git-diff-across-renamed-directories

- minor performance improvements to servlet and portlet handlers

added XmlAwareFormHttpMessageConverter, taking over the 3.0.2-introduced XML multipart support (avoiding a package cycle)

fixed @ExceptionHandler resolution in case of multiple matches at different inheritance levels (SPR-7085)

SPR-7000 - AnnotationMethodHandlerAdapter gives priority to media type order over quality when selecting a method

SPR-6009 - @ExceptionHandler methods are still expected to return a ModelAndView, even when consuming a ServletResponse/OutputStream/Writer