Upgrade to Groovy 2.2.1

Fixes gh-126

spring-boot-dependencies/pom.xml

@@ -13,7 +13,7 @@
 		<commons-dbcp.version>1.4</commons-dbcp.version>
 		<commons-pool.version>1.6</commons-pool.version>
 		<gradle.version>1.6</gradle.version>
-		<groovy.version>2.1.6</groovy.version>
+		<groovy.version>2.2.1</groovy.version>
 		<h2.version>1.3.175</h2.version>
 		<hamcrest.version>1.3</hamcrest.version>
 		<hibernate-entitymanager.version>4.3.0.Final</hibernate-entitymanager.version>