Includes revised content type handling.

Issue: SPR-15116

Issue: SPR-15082

Issue: SPR-15123

Issue: SPR-15117

Issue: SPR-15098

Issue: SPR-15090

Issue: SPR-15026

SPR-15107 Updating MySQLMaxValueIncrementer to not rely on MYISAM

Introduce mime/media types for application/rss+xml

Improve performance of StringUtils.capitalize()

This commit exposes the WebSession on ServerRequest.

We should no longer rely on MYISAM for the sequence table since this
engine might not always be available. After this change the storage
engine used by the sequence table can be MYISAM or INNODB since the
sequences are allocated using a new connection without being
affected by any other transactions that might be in progress.

To allow users to fall back on the original functionality of using
MYISAM tables for the incrementer, we add a `useNewConnection` flag to
indicate whether or not to use a new connection for the incrementer.
This flag defaults to true.

Issue: SPR-15107

This commit introduces a router DSL for RouterFunctions
and RouterFunction in order to be able to write idiomatic
Kotlin code as below:

fun route(request: ServerRequest) = RouterFunctionDsl {
    accept(TEXT_HTML).apply {
            (GET("/user/") or GET("/users/")) { findAllView() }
            GET("/user/{login}") { findViewById() }
    }
    accept(APPLICATION_JSON).apply {
            (GET("/api/user/") or GET("/api/users/")) { findAll() }
            POST("/api/user/") { create() }
            POST("/api/user/{login}") { findOne() }
    }
 } (request)

Issue: SPR-15065

Issue: SPR-15128

This commit also improve significantly Kotlin extensions
documentation.

Issue: SPR-15127

Issue: SPR-15126

val context = GenericApplicationContext {
    registerBean<Foo>()
    registerBean { Bar(it.getBean<Foo>()) }
}

Issue: SPR-15126

Issue: SPR-15119

Issue: SPR-15118

Put the lambda parameter at the end and use a function
instead of a supplier to be able to register beans like this:

val context = GenericApplicationContext()
context.registerBean(Foo::class)
context.registerBean{ Bar(it.getBean(Foo::class)) }

Issue: SPR-15118

Based on an idea from Mario Arias, we can avoid requiring specifying
explicitly Supplier lambda type in Kotlin API by declaring the supplier
parameter as "crossinline supplier: () -> T" instead of
"supplier: Supplier<T>".

Issue: SPR-15118

For now if sharedEngine is set to false, a new
ScriptEngine instance is created for each request.

Issue: SPR-15063

Issue: SPR-15112

Issue: SPR-15109

After the upgrade to JUnit Jupiter 5.0 M3, JUnit Jupiter tests in the
Spring build were no longer executed due to the introduction of a
default test class name pattern.

This commit addresses this issue by making use of the
@IncludeClassNamePatterns to specify that *TestCase test classes should
be executed within the org.springframework.test.context.junit.jupiter
package.

Issue: SPR-15106

Prior to this commit, the `ResourceHttpMessageConverter` would support
converting from an `HttpInputMessage` to a `InputStreamResource`. This
is valid when reading resources on the server side, but it's not
compatible with the way `RestTemplate` works.

The API exposed by `RestOperations` imply that the HTTP server response
should be fully consumed and properly closed by the time the `exchange`
method returns. In other words, this HTTP client does not support
streaming the HTTP response.

This commit allows the `ResourceHttpMessageConverter` to be configured
to disable read streaming when used in `RestTemplate`.

Issue: SPR-14882

* pr/1284:
  Implement MessagingException.toString()

Issue: SPR-15091
Closes gh-1284

Issue: SPR-15094

* pr/1281:
  Remove use of Boolean constructors

Codacy warns us that there are several references to Boolean
constructors in the tests. Direct usage of the Boolean constructor is
discouraged and even deprecated in Java 9 [1]. Boolean constructor use
can easily be replaced with the constant instances.

This commit contains the following changes:

 - replace references to Boolean constructors with boolean constants in
   JSP tag tests
 - update the copyright year where necessary
 - BooleanComparatorTests is intentionally left unchanged as it should
   also work with the non-constant instances correctly

 [1] http://download.java.net/java/jdk9/docs/api/java/lang/Boolean.html#Boolean-boolean-

Issue: SPR-15076

* pr/1282:
  Avoid use of double constructor of BigDecimal

Codacy warns about an Error Prone [1] use of the double constructor of
BigDecimal in tests. The reason given is that it is a source of
precision loss if the number does not have an exact double
representation. The recommendation is to use the String constructor of
BigDecimal instead as it does not require using a lossy argument.

This commit contains the following changes:

 - replace usage of the double constructor of BigDecimal with the
   String constructor of BigDecimal in JdbcTemplateQueryTests
 - update the copyright year

 [1] http://errorprone.info/bugpattern/BigDecimalLiteralDouble

Issue: SPR-15077