Rename modules {org.springframework.*=>spring-*}

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

spring-aspects/src/main/resources/META-INF/aop.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0"?>
+
+<!--
+	AspectJ load-time weaving config file to install common Spring aspects.
+-->
+<aspectj>
+
+	<!--
+	<weaver options="-showWeaveInfo"/>
+	-->
+
+	<aspects>
+		<aspect name="org.springframework.beans.factory.aspectj.AnnotationBeanConfigurerAspect"/>
+		<aspect name="org.springframework.scheduling.aspectj.AnnotationAsyncExecutionAspect"/>
+		<aspect name="org.springframework.transaction.aspectj.AnnotationTransactionAspect"/>
+		<aspect name="org.springframework.cache.aspectj.AnnotationCacheAspect"/>
+	</aspects>
+
+</aspectj>