Use @*@ delimiters in Maven resource filtering

It *is* very useful to have filtering on by default, so that is now
the case (in spring-boot-starter-parent). Users can filter resources
by default by adding @*@ placeholders (so as not to clash with Spring
${} placeholders).

Fixes gh-1199

spring-boot-samples/spring-boot-sample-actuator/src/main/resources/application.properties

@@ -18,4 +18,7 @@ shell.auth: spring
 #shell.auth.key.path: ${user.home}/test/id_rsa.pub.pem
 #shell.auth: simple
 spring.jmx.enabled: true
-
+info.group: @project.groupId@
+info.artifact: @project.artifactId@
+info.name: @project.name@
+info.version: @project.version@

spring-boot-samples/spring-boot-sample-actuator/src/test/java/sample/actuator/SampleActuatorApplicationTests.java

@@ -145,6 +145,15 @@ public class SampleActuatorApplicationTests {
 				entity.getBody().contains("\"hello\":1"));
 	}
 
+	@Test
+	public void testInfo() throws Exception {
+		ResponseEntity<String> entity = new TestRestTemplate().getForEntity(
+				"http://localhost:" + this.port + "/info", String.class);
+		assertEquals(HttpStatus.OK, entity.getStatusCode());
+		assertTrue("Wrong body: " + entity.getBody(),
+				entity.getBody().contains("\"artifact\":\"spring-boot-sample-actuator\""));
+	}
+
 	@Test
 	public void testErrorPage() throws Exception {
 		ResponseEntity<String> entity = new TestRestTemplate("user", getPassword())