Wired AuditMethodInterceptor into new audit framework

- Two new repo properties to control auditing:
     audit.enabled=false
     audit.useNewConfig=false
 - Auditing was enabled by default, but it is not enabled any more!
   The property has to be set in alfresco-global.properties
 - Unit tests for auditing successful and failed authentication attempts


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@16496 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/audit/AuditComponent.java

@@ -168,7 +168,8 @@ public interface AuditComponent
      * The return values reflect what was actually persisted and is controlled by the data extractors
      * defined in the audit configuration.
      * <p/>
-     * This is a read-write method.  Client code must wrap calls in the appropriate transactional wrappers.
+     * A new read-write transaction is started if there are values to write that there is not a viable
+     * transaction present.
      * 
      * @param rootPath          a base path of {@link AuditPath} key entries concatenated with the path separator
      *                          '/' ({@link AuditApplication#AUDIT_PATH_SEPARATOR})