Update MockRestServiceServer example in reference manual

Issue: SPR-11486

Issue: SPR-11500

The Servlet API does not provide notifications when a client
disconnects, see see https://java.net/jira/browse/SERVLET_SPEC-44.
Therefore network IO failures may occur simply because a client has
gone away. Before this change that could fill logs with unnecessary
stack traces.

After this change we make a best effort to identify such network
failures, on a per-server basis (tested with Jetty, Tomcat, Glassfish,
and WildFly), and log them under a separate log category.

A simple one-line message is logged at DEBUG level (i.e. no stack trace)
while a full stack trace is shown at TRACE level.

Issue: SPR-11438

 - "__ `text`__" --> "__`text`__"

 - "`text` s" --> "`text`s"

* SPR-11459:
  Update ref. manual to favor constructor injection

The breakout box named "Constructor-based or setter-based DI?" in the
reference manual currently recommends the use of setter injection.

This commit refines this text to align with current best practices and
now favors constructor injection over setter injection.

Issue: SPR-11459

Also removed outdated Struts references and made use of 'javadocs' term consistent.

Issue: SPR-11473

Issue: SPR-11478

Issue: SPR-11492

Issue: SPR-11488

Allow Jaxb2RootElementHttpMessageConverter subclasses to customize
the {@link Marshaller} and the {@link Unmarshaller} created by the
message converter.

Issue: SPR-11488

SpringSource github org name changed to spring-projects.

AbstractDispatcherServletInitializer now adds a unique suffix to a
filter name if it fails to register it.

Issue: SPR-11493

Prior to this commit, one had to provide her own
RequestMappingHandlerMapping instance (i.e extend
WebMvcConfigurationSupport and override the requestMappingHandlerMapping
method) in order to customize path matching properties on that bean.

Since SPR-10163, XML config users can do that using the
<mvc:path-matching/> XML tag. This commit adds the same feature to MVC
Java config with a PathMatchConfigurer.

Issue: SPR-11486

Issue: SPR-10441

Issue: SPR-11477

Before this change CompositeMessageConverter had a ContentTypeResolver
field that was in turn set on all contained converters.

After this change that field is removed and effectively
CompositeMessageConverter is a simple container of other converters.
Each converter in turn must have been configured with a
ContentTypeResolver.

Doing so means it is less likely to have unexpected consequences when
configuring converters, the ContentTypeResolver set in the composite
converter overriding the one configured in a contained converter.

Also commit 676ce6 added default ContentTypeResolver initialization
to AbstractMessageConverter, which ensures that converters are still
straight forward to configure.

Issue: SPR-11462

Previously AbstractMessageConverter did not have a ContentTypeResolver
configured by default. However the Java config and XML namespace in
spring-messaging and spring-websocket always configured one.

This change ensures every AbstractMessageConverter is configured with an
instance of DefaultContentTypeResolver by default. This makes sense since
all the resolver does is make an attempt to find a content type to use
for matching. If it can't it returns null and it's up to the converter
to decide whether it can convert or not.

Issue: SPR-11462

Issue: SPR-11484

AbstractMessageConverter now supports a strictContentTypeMatching mode
in which the content type of a message must be resolved to a (non-null)
value that matches one of the configured supported MIME types in order
for the converter to be used.

Issue: SPR-11463

After this change DefaultContentTypeResolver supports String-based
"contentType" header values in addition to MimeType-based.

Issue: SPR-11461

This commit:
* adds a reference to the Spring Code Style wiki page in the main
CONTRIBUTING document
* updates the link to the Spring team in README
* adds a note regarding Intellij IDEA 13 issues

The previous commit introduced a dependency on
Class.getDeclaredAnnotation() which is a Java 8 API.

This commit refactors AnnotationUtils.findAnnotation(Class, Class, Set)
to use Class.getAnnotation() in conjunction with
isAnnotationDeclaredLocally() in order to achieve the same desired
behavior.

Issue: SPR-11475

* SPR-11475:
  Favor 'local' annotations over inherited ones

Prior to this commit, the implementations of findAnnotation() in
AnnotationUtils and getAnnotationAttributes() in AnnotatedElementUtils
favored inherited annotations and inherited composed annotations over
composed annotations that are declared closer to the starting class
passed to these methods.

This commit addresses this issue as follows:

- Refactored AnnotationUtils to use getDeclaredAnnotation() and
  getDeclaredAnnotations() instead of getAnnotation() and
  getAnnotations() where appropriate.

- AnnotatedElementUtils.doProcess() supports a traverseClassHierarchy
  flag to control whether the class hierarchy should be traversed,
  using getDeclaredAnnotations() instead of getAnnotations() if the
  flag is true.

- Overhauled Javadoc in AnnotatedElementUtils.

Issue: SPR-11475