Auto-configure Spring Security OAuth2 when detected on the classpath

* Automatically spin up Authorization Server and Resource Server
* Automatically configures method level security included OAuth2Expression handler
* Wrote extensive unit tests verifying default behavior as well as the auto-configuration backing off when custom Authorization/Resource servers are included
* Created org.springframework.boot.security.oauth2 subpackage to contain it
* Can also disable either resource of authorization server completely with a single property for each
* Print out the auto-generated secrets and other settings
* Added spring-boot-sample-secure-oauth2 to provide a sample that can be run and poked with curl as well as some automated tests.
* Make users ask for which servers to install by adding @Enable*
* User has to @EnableGlobalMethodSecurity instead of using properties files

Add Spring Security OAuth2 support to Spring Boot CLI

* Triggered from either @EnableAuthorizationServer or @EnableResourceServer
* Needs to have @EnableGlobalMethodSecurity to allow picking the annotation model.
* By default, comes with import support for @PreAuthorize, @PreFilter, @PostAuthorize, and @PostFilter via a single start import
* Also need import support for the enable annotations mentioned above.
* Added extra test case and sample (oauth2.groovy)

spring-boot-samples/spring-boot-sample-secure-oauth2/src/main/java/sample/FlightRepository.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2012-2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package sample;
+
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.security.access.prepost.PreAuthorize;
+
+/**
+ * Spring Data interface with secured methods
+ *
+ * @author Craig Walls
+ * @author Greg Turnquist
+ */
+public interface FlightRepository extends CrudRepository<Flight, Long> {
+
+	@PreAuthorize("#oauth2.hasScope('read')")
+	@Override
+	Iterable<Flight> findAll();
+
+	@PreAuthorize("#oauth2.hasScope('read')")
+	@Override
+	Flight findOne(Long aLong);
+
+	@PreAuthorize("#oauth2.hasScope('write')")
+	@Override
+	<S extends Flight> S save(S entity);
+}