BeanNameViewResolver ignores non-View beans

Issue: SPR-12079
Polishing

Issue: SPR-12079
Support Jackson based XML serialization/deserialization

This commit adds support for XML serialization/deserialization based on
the jackson-dataformat-xml extension. When using @EnableWebMvc or
<mvc:annotation-driven/>, Jackson will be used  by default instead of JAXB2
if jackson-dataformat-xml classes are found in the classpath.

This commit introduces MappingJackson2XmlHttpMessageConverter and
MappingJackson2XmlView classes, and common parts between JSON
and XML processing have been moved to AbstractJackson2HttpMessageConverter
and AbstractJackson2View classes.

MappingJackson2XmlView supports serialization of a single object. If the model
contains multiple entries, MappingJackson2XmlView.setModelKey() should be
used to specify the entry to serialize.

Pretty print works in XML, but tests are not included since a Woodstox dependency
is needed, and it is better to continue testing spring-web and spring-webmvc
against JAXB2.

Issue: SPR-11785
Introduce @TestPropertySource support in the TCF

Spring Framework 3.1 introduced an Environment abstraction with support
for hierarchical PropertySources that can be configured
programmatically as well as declaratively via the @PropertySource
annotation. However, prior to this commit, there was no way to
declaratively configure PropertySources in integration tests in the
Spring TestContext Framework (TCF).

This commit introduces declarative support for PropertySources in the
TCF via a new class-level @TestPropertySource annotation. This
annotation provides two options for declaring test property sources:

 - The 'locations' attribute allows developers to declare external
   resource locations for test properties files.

 - The 'properties' attribute allows developers to declare inlined
   properties in the form of key-value pairs.

Test properties files are added to the Environment before all other
property sources and can therefore override system and application
property sources. Similarly, inlined properties are added to the
Environment before all other property sources and can therefore
override system property sources, application property sources, and
test properties files.

Specifically, this commit introduces the following major changes:

 - Introduced @TestPropertySource annotation along with internal
   TestPropertySourceAttributes, MergedTestPropertySources, and
   TestPropertySourceUtils for working with test property sources
   within the TCF.

 - All TestContextBootstrappers have been modified to support the
   merged property resource locations and inlined properties from
   @TestPropertySource.

 - MergedContextConfiguration (and consequently the context caching
   key) is now additionally based on the merged property resource
   locations and inlined properties from @TestPropertySource. The same
   applies to WebMergedContextConfiguration.

 - AbstractContextLoader's prepareContext() method now adds
   PropertySources for all resource locations and inlined properties
   from the supplied MergedContextConfiguration to the Environment of
   the supplied ApplicationContext. All subclasses of
   AbstractGenericContextLoader and AbstractGenericWebContextLoader
   therefore automatically provide support for @TestPropertySource.

Issue: SPR-12051
Merge from sbrannen/SPR-12051

* SPR-12051:
  Introduce @TestPropertySource support in the TCF
Add @Deprecated to WebMergedContextConfiguration constructor
Clean up regarding deprecated HttpStatus.MOVED_TEMPORARILY
Delete trailing white space in spring-test
Improve ex msg when locations & classes are declared in test hierarchy

Prior to this commit, if both locations and classes were declared via
@ContextConfiguration at differing levels in a test class hierarchy,
the exception message stated that neither of the default context
loaders was able to load an ApplicationContext from the merged context
configuration, but the message didn't explain why.

This commit adds an explicit check for such scenarios and provides a
more informative exception message similar to the following:

"Neither X nor Y supports loading an ApplicationContext from
[MergedContextConfiguration ...]: declare either 'locations' or
'classes' but not both."

Issue: SPR-12060
Allow null ObjectMapper in Jackson2ObjectMapperFactoryBean.getObjectType()

Issue: SPR-11785
Add tests for ImportSelector meta-data

Issue: SPR-12059
Support automatic discovery of default TELs

Prior to this commit, there was no declarative mechanism for a custom
TestExecutionListener to be registered as a default
TestExecutionListener.

This commit introduces support for discovering default
TestExecutionListener implementations via the SpringFactoriesLoader
mechanism. Specifically, the spring-test module declares all core
default TestExecutionListeners under the
org.springframework.test.context.TestExecutionListener key in its
META-INF/spring.factories properties file, and third-party frameworks
and developers can contribute to the list of default
TestExecutionListeners in the same manner.

 - AbstractTestContextBootstrapper uses the SpringFactoriesLoader to
   look up the class names of all registered default
   TestExecutionListeners and sorts the instantiated listeners using
   AnnotationAwareOrderComparator.

 - DefaultTestContextBootstrapper and WebTestContextBootstrapper now
   rely on the SpringFactoriesLoader mechanism for finding default
   TestExecutionListeners instead of hard coding fully qualified class
   names.

 - To ensure that default TestExecutionListeners are registered in the
   correct order, each can implement Ordered or declare @Order.

 - AbstractTestExecutionListener and all default TestExecutionListeners
   provided by Spring now implement Ordered with appropriate values.

 - Introduced "copy constructors" in MergedContextConfiguration and
   WebMergedContextConfiguration

 - SpringFactoriesLoader now uses AnnotationAwareOrderComparator
   instead of OrderComparator.

Issue: SPR-11466
Merge from sbrannen/SPR-11466

* SPR-11466:
  Support automatic discovery of default TELs
Lookup methods can support arguments, find a target bean based on the return type, and be identified by an @Lookup annotation

Issue: SPR-7431
Issue: SPR-5192
Polishing
Fixed fragile tests for @Bean method overloading
Polishing
Support merging custom TELs with default TELs

Prior to this commit, if a custom TestExecutionListener was registered
via @TestExecutionListeners the defaults would not be registered. Thus,
if a user wanted to declare a custom listener and use the default
listeners, the user was forced to manually declare all default
listeners in addition to any custom listeners. This unfortunately
required that the user know exactly which listeners were registered by
default. Moreover, the set of default listeners can change from release
to release, and with the support for automatic discovery of default
listeners introduced in SPR-11466 it is no longer even possible to know
what the set of default TestExecutionListeners is before runtime.

This commit addresses this issue by introducing a mechanism for merging
custom declared listeners with the defaults for the current
environment. Specifically, @TestExecutionListeners supports a new
MergeMode that is used to control whether or not explicitly declared
listeners are merged with the default listeners when
@TestExecutionListeners is declared on a class that does not inherit
listeners from a superclass.

Issue: SPR-8854
Polishing
Polish Javadoc and formatting in @TestExecutionListeners