The following style updates have been made in anticipation of
substantive changes in subsequent commits:

 - organize imports
 - correct whitespace errors (leading spaces in code, tabs in Javadoc)
 - wrap Javadoc at 90 chars; make imperative ("Return" vs. "Returns")
 - use conventional constructor argument wrapping

A serialVersionUID has also been added to RestClientException and its
ResourceAccessException subclass for consistency with the rest of that
same exception hierarchy.

Issue: SPR-7938

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

SPR-8883 - RestTemplate.headForHeaders throws "IllegalArgumentException: No InputStream specified" on server resource which status code are 4xx

refactored HTTP support into top-level package "org.springframework.http"; revised RestTemplate facility in package "org.springframework.web.client"