This renaming more intuitively expresses the relationship between
subprojects and the JAR artifacts they produce.

Tracking history across these renames is possible, but it requires
use of the --follow flag to `git log`, for example

    $ git log spring-aop/src/main/java/org/springframework/aop/Advisor.java

will show history up until the renaming event, where

    $ git log --follow spring-aop/src/main/java/org/springframework/aop/Advisor.java

will show history for all changes to the file, before and after the
renaming.

See http://chrisbeams.com/git-diff-across-renamed-directories

Servlet/Portlet ApplicationContexts use a specific id based on servlet/portlet name; DefaultListableBeanFactory references are serializable now when initialized with an id; scoped proxies are serializable now, for web scopes as well as for singleton beans; injected request/session references are serializable proxies for the current request now