Added info-level logging for default unit detection

Issue: SPR-11333
Consistent evaluation of empty theme names to default theme name

Issue: SPR-11128
Locale/ThemeChangeInterceptor alignment and javadoc polishing

Issue: SPR-11128
Resolve native header values with @Header

The @Header annotation in spring-messaging now resolves values from the
nested "nativeHeaders" map as well as top-level header map values.

In case of ambiguity (a value that exists in both), the top-level map
value is used and a warning message is printed. This is unlikly in most
cases but can be resolved by prefixing the header value with
"nativeHeadres.myHeader".

Issue: SPR-11326
Fix warnings in HeaderMethodArgumentResolver
Roll back jexcelapi from 2.6.12 to 2.6.3

JExcelAPI 2.6.12 appears to be causing ArrayIndexOutOfBoundsException
with the build. Rolling back to the earlier version for now
General ExcelViewTests code update

Issue: SPR-11334
Polishing
Deprecated AbstractJExcelView since JExcelAPI is an abandoned project

JXL had no release since 2009, and has some serious bugs remaining: e.g. JXL on Unix cannot read template files created on Windows, using the 'latest' JXL 2.6.12 release.
Consider wildcard type without bounds as eligible for fallback match too

Issue: SPR-11250
Upgrade to jexcelapi 2.6.12 and fix test failures

Upgrade to the latest release of jexcelapi and work-around the
ArrayIndexOutOfBounds test exception on *nix machines.

Issue: SPR-11334
Allow HttpHeaders return values for @MVC methods

Allow HttpHeader instances to be returned directly from MVC controller
methods managed by HandlerMethodReturnValueHandler rather than needing
to be wrapped in a ResponseEntity.

Issue: SPR-11129
Polish

Issue: SPR-11129
Revert previous impl for SPR-10163

This reverts commit 96b418cc8ae537e985cfe67b80cd866d03c8060f,
"Make RequestMappingHandlerMapping xml config easier".

This implementation makes the mvc:annotation namespace less readable,
and future configuration items would add even more to this namespace.

Issue: SPR-10163
Make RequestMappingHandlerMapping xml config easier

Prior to this commit, it was necessary to override
the HandlerMapping definition to change properties
like useSuffixPatternMatch, useSuffixPatternMatch...
Also, one couldn't set custom pathmatcher/pathhelper
on RequestMappingHandlerMapping via XML configuration.

This commits adds a new "mvc:annotation-driven"
subelement called "mvc:path-matching" for the tag
that allows to configure such properties:
* suffix-pattern
* trailing-slash
* registered-suffixes-only
* path-matcher
* path-helper

Note: this is a new take on this issue, since
96b418cc has been reverted by e2b99c3.

Issue: SPR-10163
RemoteInvocation(Result) explicitly designed for JavaBean-style deserialization

Issue: SPR-11337
Introduce hibernate3Version constant in Gradle build
Ensure all tests in spring-test are executed

Prior to this commit TestNG tests would only be executed by the Gradle
build if they were located in the “testng” package. Tests in subpackages
would therefore be omitted from the build.

This commit ensures that all TestNG classes in the “testng” package and
any of its subpackages are executed in the Gradle build.

Furthermore, this commit ensures that the JUnit-based
FailingBeforeAndAfterMethodsTests test class is executed along with the
other JUnit tests even though it resides under the “testng” package.

Issue: SPR-11338
Include ServletTEL in abstract base test classes

The ServletTestExecutionListener is now prepended to the set of default
listeners in AbstractJUnit4SpringContextTests and
AbstractTestNGSpringContextTests.

Issue: SPR-11340
DefaultPersistenceUnitManager detects META-INF/orm.xml for scanned default unit

Note: A default orm.xml file is only being used when not co-located with a persistence.xml file, since we assume it is intended for use with that persistence.xml file only then.

Issue: SPR-11234
Issue: SPR-11260