SEC-1998: Provide integration with WebAsyncManager#startCallableProcessing

Support integration of the Spring SecurityContext on Callable's used with
WebAsyncManager by registering SecurityContextCallableProcessingInterceptor.

samples/openid/openid.gradle

@@ -7,7 +7,7 @@ dependencies {
     compile project(':spring-security-core'),
             project(':spring-security-openid')
 
-    providedCompile 'javax.servlet:servlet-api:2.5@jar'
+    providedCompile "org.apache.tomcat:tomcat-servlet-api:$servletApiVersion"
 
     runtime project(':spring-security-config'),
             project(':spring-security-taglibs'),