Fix and refactor spring-aspects build

- Fix compileTestJava issue in which test classes were not being
   compiled or run

 - Use built-in eclipse.project DSL instead of withXml closure
   to add AspectJ nature and builder

 - Rename {aspectJ=>aspects}.gradle and format source

build.gradle

@@ -432,7 +432,7 @@ project('spring-struts') {
 
 project('spring-aspects') {
     description = 'Spring Aspects'
-    apply from: 'aspectJ.gradle'
+    apply from: 'aspects.gradle'
     dependencies {
         compile project(":spring-orm")
         aspects project(":spring-orm")
@@ -440,6 +440,10 @@ project('spring-aspects') {
         compile "org.aspectj:aspectjrt:1.6.8"
         testCompile project(":spring-test")
     }
+    eclipse.project {
+        natures += 'org.eclipse.ajdt.ui.ajnature'
+        buildCommand 'org.eclipse.ajdt.core.ajbuilder'
+    }
 }
 
 configure(rootProject) {