Issue: SPR-9321

Hibernate synchronization properly unbinds Session even in case of afterCompletion exception (SPR-8757)

Following the move to git, empty dirs are not tracked. Add .gitignore
files as necessary to keep the ant build happy.

spring-build was previously included via an svn:external. Adding
directly to the source tree under Git to avoid the need for a git
submodule.

In order to build from any earlier commit, it is recommended to
export spring-build or symlink an existing copy into the root
of the spring-framework project and then build normally.

    $ svn export https://src.springsource.org/svn/spring-build/tags/project-build-2.5.2 spring-build

@Transactional qualifiers match against transaction manager definitions in parent contexts as well (SPR-7679)

ResourceHttpRequestHandler sends content without content-type header if no media type found (SPR-7713)

Portlet session mutex uses global session attribute to be shared among all portlets in the session (SPR-8888)

ConversionService prevents Converter from trying to convert to a subtype of its actual target type (SPR-8718)

CollectionCollection/MapToMapConverter preserve original Collection/Map if no converted elements (SPR-8714)