This commit introduces template rendering support in the web.reactive
package, through a Response.render method and a Rendering interface.

From context, It seems that the first word "method" is needless,

Issue: SPR-14557

Issue: SPR-14557

Issue: SPR-13965

HibernateTemplate reflectively calls getNamedQuery (for runtime compatibility with Hibernate 5.0/5.1 vs 5.2)

Issue: SPR-14676

Issue: SPR-14672

* pr/1165:
  Fix typo

There is no attribute named `path` in `@RequestParam`, so I change it to
`name`.

Closes gh-1165

This commit changes the default file extension configured with
`AppCacheManifestTranformer`. This ResourceTransformer was previously
considering `.manifest` files by default, but this has been changed in
the official spec to `appcache`, in order not to clash with Microsoft's
unregistered application/manifest type.

Issue: SPR-14687

`ResolvedResource` is a rather generic name - changing the extended
interface to something more meaningful: `HttpResource`.
For now, implementations are linked with the resource handling chain,
but this aspect has been removed from the interface documentation.

Issue: SPR-14264

* spock_model_and_view:
  Fix using system default charset in view rendering
  Changed View.render method to take Map<String, ?>

Prior to this commit, FreeMarkerView used the system default charset to
render. This commit switches this by defaulting to UTF-8, if no charset
is specified in the content type.

 - Add contentType parameter to AbstractView.renderInternal, used to
 determine the charset contained therein
 - Adds a defaultCharset property to AbstractView and
 ViewResolverSupport.

Changed View's render method from taking a HandlerResult to taking a
Map<String, ?>, in order to facilitate scenarios where a HandlerResult
is not available (i.e. web.reactive.function).

 - Changed Response.sse methods to allow for specific Publisher types to
 be returned in Response.

Two changes to web.reactive.function:

 - Changed Response.stream method to allow for specific Publisher types
 to be returned in Response.

 - Router now stores HttpMessageReader|Writer retrieved from
 Configuration in the attributes as supplier, not as stream, to allow
 for multiple reads.

Sources should be using UTF-8.

Issue: SPR-14674

Removes attributes() method from Request, as it exposes a mutable map.

Prior to this commit, the resource handling chain and its
`ResourceResolvers` would use specific `Resource` implementations in
order to add resource metadata to the HTTP response. For example,
`VersionedResource` and `EncodedResource` are both adding specific HTTP
response headers.

This commit aims at making this mechanism more stable and reusable,
since the previous implementation would fail in case a resolved resource
would be both a `VersionedResource` wrapping a `EncodedResource` (or the
other way arount). Only one of the specific implementations would
contribute its metadata since the code supporting that in
`ResourceHttpRequestHandler` would only check for `instanceof` tests,
whereas those implementations are acutally delegating calls to
the wrapped resource.

Now both `VersionedResource` and `EncodedResource` have been replaced by
specific implementations of `ResolvedResource`, which directly provides
those HTTP response headers as part of `getResponseHeaders()`.

This commit applies the same changes for the web reactive
implementations and its `ResourceWebHandler`.

Issue: SPR-14264

* pr/1158:
  Fix typo

Closes gh-1158

Since SPR-14522, the web reactive framework supports checkNotModified
features. This commit aligns the existing MVC infrastructure with
web reactive's behavior.

Because of the new Servlet 3.0 baseline, some constraints
aren't relevant anymore and duplicate code has been removed in
`HttpEntityMethodProcessor`.

Issue: SPR-14659

Issue: SPR-14521

A straight-forward port of the resource handling support in
spring-webmvc to spring-web-reactive. Primarily adapting contracts and
implementations to use the reactive request and response and the
reactive ResourceHttpMessageWriter.

Issue: SPR-14521

Issue: SPR-5863

Issue: SPR-5863

Issue: SPR-4365

Whereas the existing TestContextConcurrencyTests verify support for
concurrency in the TestContextManager and TestContext, this commit
introduces SpringJUnit4ConcurrencyTests that verify support for
concurrent test execution in Spring's JUnit 4 support, namely in the
SpringRunner, SpringClassRule, and SpringMethodRule.

The tests executed by this new test class come from a hand-picked
collection of test classes within the test suite that is intended to
cover most categories of tests that are currently supported by the
TestContext Framework on JUnit 4.

Note, however, that the chosen test classes intentionally do not
include any classes that fall under the following categories.

 - tests that make use of Spring's @DirtiesContext support

 - tests that make use of JUnit 4's @FixMethodOrder support

 - tests that commit changes to the state of a shared in-memory database

Issue: SPR-5863

This commit improves the exception message thrown when a test's
ApplicationContext is no longer active by explaining that the cause
may be due to parallel test execution.

Issue: SPR-5863

Issue: SPR-5863