(cherry picked from commit f9339417)

Prior to this change the SpEL compiler would not compile mathematical
expressions where the operands were of differing types (e.g. int
and double). This required the expression writer to do the conversion
in the expression text. For example:

T(Integer).valueOf(someInt).doubleValue()/35d

With this commit the restriction is lifted and it is more like Java
so that you can simply do someInt/35d. The mathematical operators
affected are divide/plus/minus/multiply and modulus. This change
involved removing some guards so that the exitTypeDescriptor (the
trigger for whether compilation is allowed) is set more frequently
and enhancing bytecode generation to perform more sophisticated
conversion/coercion automatically.

Issue: SPR-12789

We use AspectJ 1.9.0.BETA-1 for the ajc task now and exclude spring-oxm test compilation when running on JDK 9.

Issue: SPR-12549

Issue: SPR-12778

AbstractPlatformTransactionManager logs warning for custom isolation level in case of no actual transaction

Issue: SPR-12600

(Reloadable)ResourceBundleMessageSource allows for custom PropertyResourceBundle/Properties subclasses

Issue: SPR-12666

Core and Web chapters are important chapters in the Spring Framework
reference documentation, and splitting them in multiple files will
help to evolve the documentation while not creating too many files.

Issue: SPR-12309

Collections.unmodifiableMultiValueMap explicitly casts to List<V> (for compatibility with JDK 9 build 53)

Issue: SPR-12549

Issue: SPR-12786

The reference documentation is now organized in asciidoc bookparts.
Bookparts sections can be also put in separate files, when their
size and theme are important enough to justify that.

Documentation Layout:
```
index
  |-- overview
  |
  |-- whats-new
  |
  |-- core
  |   |-- core-beans
  |   |-- core-aop
  |-- testing
  |
  |-- data-access
  |
  |-- web
  |   |-- web-mvc
  |   |-- web-view
  |-- integration
  |
  |-- appendix
      |-- appx-spring-tld
      |-- appx-spring-form-tld
```

Supersedes and closes #641

Issue: SPR-12309

Upgrade to asciidoctor-gradle-plugin version 1.5.2.
Various syntax fixes in the index.adoc reference documentation.

All HttpMessageConverters should support StreamingHttpOutputMessage.
Specifically, the BufferedImageHttpMessageConverter and
FormHttpMessageConverter should do so.

Issue: SPR-12715

Issue: SPR-12771

This commit adds the following to gradle.properties in order to execute
the Gradle daemon on JDK 9, since Gradle's DaemonParameters
automatically sets the MaxPermSize JVM argument, which is no longer
supported on JDK 9.

org.gradle.jvmargs=-XX:MaxMetaspaceSize=1024m -Xmx1024m

Issue: SPR-12549

Issue: SPR-12549

Issue: SPR-12788

Issue: SPR-12785

Issue: SPR-12780

Issue: SPR-12761

Previously, adding `@EnableAsync` on a blank application would lead to an
info message stating that `ProxyAsyncConfiguration` is not eligible for
getting processed by all BeanPostProcessors. Concretely, this is ok as
such internal configuration is not meant to be a target of such post
processing.

Revisit the condition for non infrastructure bean only. Add the
infrastructure role to a set of internal configuration, including the
`ProxyAsyncConfiguration`.

Issue: SPR-12761

Support the creation and registration of message listener containers in
a lazy manner, that is after the container initialization has completed.

Such support brought an interesting brainstorming of the thread safety
if JmsListenerEndpointRegistrar and JmsListenerEndpointRegistry so those
have also been revisited as part of this commit.

Issue: SPR-12774

(cherry picked from commit 37835910)

Issue: SPR-12776
(cherry picked from commit 1259671f)

Latest dependency updates (HttpClient 4.4, TestNG 6.8.21, SnakeYAML 1.15, FreeMarker 2.3.22, JRuby 1.7.19, JAMon 2.81, JiBX 1.2.6, XMLUnit 1.6, JsonPath 1.2)

Revert cdc04e55 now that animal sniffer 1.1.4 is available.

This commit simplifies the implementations of loadBeanDefinitions() in
GenericGroovyXmlContextLoader and GenericGroovyXmlWebContextLoader.

Due to the recent bug fix for GroovyBeanDefinitionReader regarding full
support for XML config files, these Groovy context loaders can now
simply use a GroovyBeanDefinitionReader instead of a
GroovyBeanDefinitionReader plus an XmlBeanDefinitionReader.

Issue: SPR-12769

Prior to this commit, the GroovyBeanDefinitionReader claimed (via its
Javadoc) that it fully supported XML configuration files in addition to
its Groovy DSL; however, this was unfortunately inaccurate since XML
validation was disabled by default which led to certain features of XML
configuration not working. For example, it was impossible to define a
<qualifier> in an XML config file without specifying the 'type'
attribute (which has a default value defined in the spring-beans XSD).

This commit fixes this issue by ensuring that bean definitions in XML
resources are loaded with a "standard" XmlBeanDefinitionReader that is
created with default settings (i.e., with XML validation enabled). With
regard to backwards compatibility, bean definitions defined using the
Groovy DSL are still loaded with an XmlBeanDefinitionReader that has
XML validation disabled by default which is necessary for proper
parsing of the Groovy DSL.

Issue: SPR-12769

Prior to this commit, it was impossible to use all features of XML
configuration (e.g., the <qualifier> tag) in web-based integration
tests (loaded using @WebAppConfiguration, @ContextConfiguration, etc.)
if the Groovy library was on the classpath. The reason is that the
GroovyBeanDefinitionReader used internally by
GenericGroovyXmlWebContextLoader disables XML validation for its
internal XmlBeanDefinitionReader, and this prevents some XML
configuration features from working properly. For example, the default
value for the 'type' attribute (defined in the spring-beans XSD) of the
<qualifier> tag gets ignored, resulting in an exception when the
application context is loaded.

This commit addresses this issue by refactoring the implementation of
loadBeanDefinitions() in GenericGroovyXmlWebContextLoader to use an
XmlBeanDefinitionReader or GroovyBeanDefinitionReader depending on the
file extension of the resource location from which bean definitions
should be loaded. This aligns the functionality of
GenericGroovyXmlWebContextLoader with the existing functionality of
GenericGroovyXmlContextLoader.

Issue: SPR-12768

Prior to this commit, the implementation of equals() in EncodedResource
was based solely on the resource and encoding. Thus, if a Charset were
specified instead of an encoding, invocations of equals() would not
work as expected.

This commit addresses this issue by including the charset in the
implementation of equals() and introducing corresponding tests in a new
EncodedResourceTests class. Furthermore, this commit makes
EncodedResource immutable and updates all Javadoc to reflect support
for the encoding and charset properties.

Issue: SPR-12767

Issue: SPR-12766

Issue: SPR-12752