Fix  HttpUrlConnection DELETE without body

The following commit allowed HTTP DELETE with body:
https://github.com/spring-projects/spring-framework/commit/584b831bb9390a49c791d180d023e3a585203215

However it broke buffered requests even without a body since JDK 1.6
and 1.7 do not support calls to getOutputStream with HTTP DELETE.

This commit set the doOutput flag back to false if the actual buffered
body is 0 length.

Issue: SPR-12361
Consistent declaration and use of UTF-8 Charset constants, plus related polishing
Polishing
Apply extra checks to static resource handling

- remove leading '/' and control chars
- improve url and relative path checks
- account for URL encoding
- add isResourceUnderLocation final verification

Issue: SPR-12354
Next Development Version
Add Id to JmsListenerEndpoint Docs

Issue: SPR-12425
Merge pull request #692 from garyrussell/SPR-12425

* SPR-12425:
  Add Id to JmsListenerEndpoint Docs
Fix bytecode generation for SpEL OpPlus

Without this change the plus operator would fail to
include a CHECKCAST in generated bytecode when it
was compiled in cases where one of the operands
has a runtime type of String but a statically
declared type that was not String (i.e. Object).

Issue: SPR-12426
Allow non-String args in JOptCommandLinePropertySource

Prior to this commit, JOptCommandLinePropertySource prevented the
possibility of non-String option arguments. This effectively prevents
the use of JOpt's #ofType support (which allows specifying custom
argument types).

Now, non-String arguments are detected and converted to strings as
necessary. JOpt's #ofType now works as expected. A test has been added
to cover this case.
Use https for maven repositories
Fix user destination parsing in simp messaging

This commit fixes the parsing of message destinations such as
"/user/anna/queue/foo", reverting a regression introduced by SPR-11506,
which worked well with @SendToUser use cases but caused issues for
messages sent to other users.

Issue: SPR-12444
BeanMethodInterceptor forwards user-provided arguments to getBean(name, args)

Issue: SPR-12443
GroovyBeanDefinitionReader consistently throws BeanDefinitionParsingException for invalid files of any name

Issue: SPR-12435
MutablePropertySources uses an internal CopyOnWriteArrayList for defensiveness against concurrent modifications

Issue: SPR-12428
MethodParameter generally uses volatile variables where applicable now (as well as a local copy of the parameterNameDiscoverer field)

Issue: SPR-12453
Unit test for JavaBeans introspection against FreeMarker Configuration class

Issue: SPR-12448
RequestMappingHandlerAdapter allows for overriding handleInternal

Issue: SPR-12460
Rearranged WebAsyncTask constructor interdependencies and assertions

Issue: SPR-12457
Polishing
AnnotationBeanPostProcessors defensively catch and translate NoClassDefFoundErrors from class introspection

Issue: SPR-12461