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

spring-framework-reference/.project

@@ -1,8 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<projectDescription>
-	<name>spring-framework-reference</name>
-	<comment></comment>
-	<projects></projects>
-	<buildSpec></buildSpec>
-	<natures></natures>
-</projectDescription>