Introduce Gradle-based build

- Use recent Gradle 1.0-milestone-8 snapshot
 - Add initial cut of build.gradle able to compile/test all modules
 - Update .gitignore
 - Generate Gradle wrapper scripts
 - Remove all Eclipse metadata files
 - Temporarily @Ignore tests that do not pass under Gradle

.gitignore

@@ -10,9 +10,16 @@ integration-repo
 ivy-cache
 jxl.log
 jmx.log
-org.springframework.jdbc/derby.log
-org.springframework.spring-parent/.classpath
-org.springframework.spring-parent/.project
-org.springframework.test/test-output/
-target
-spring-build/lib/docbook
+spring-jdbc/derby.log
+spring-test/test-output/
+.gradle
+build
+.classpath
+.project
+argfile*
+
+# IDEA metadata and output dirs
+*.iml
+*.ipr
+*.iws
+out