Only retrieve the FlashMapManager if a non-empty output FlashMap has been found

Issue: SPR-10937
Perform setParent's Environment merging for ClassPathXmlApplicationContext etc constructors with parent argument as well

Issue: SPR-11068
Disable ext entities in SourceHttpMessageConverter

This change disables the processing of external entities in
SourceHttpMessageConverter by default and provides an option to enable
it if required.
Use final keyword in MessageHeaders
Fix exception mock request builder

Issue: SPR-11043
Fold spring-test-mvc sources into spring-test

With spring-test compiling against Servlet 3.0 it is no longer required
to compile Spring MVC Test sources separately (from spring-test).
Poish asciidoctor

Issues: SPR-10960
grate documentation to #	deleted:    src/reference/docbook/index.xml
Poish asciidoctor

Issues: SPR-10960
Return 415 on bad request body content-type

Issue: SPR-10982
Poish asciidoctor

Issues: SPR-10960
JndiObjectFactoryBean converts a "defaultObject" value to the expected type if necessary

Issue: SPR-11039
Added test for placeholder in alias definition

Issue: SPR-11018
Add div around extra hidden fields in FormTag

Issue: SPR-10926
Handle UnsupportedOperationException from getInstalledExtensions in Glassfish 4.0