config UPDATE add config replace test

Added test for replacing configuration data. Renamed configuration setup
API calls. Added loading JSON from files.
diff --git a/examples/server.c b/examples/server.c
index c28db62..2ca2215 100644
--- a/examples/server.c
+++ b/examples/server.c
@@ -256,7 +256,7 @@
     }
 
     /* apply the created configuration data */
-    rc = nc_server_config_setup(config);
+    rc = nc_server_config_setup_diff(config);
     if (rc) {
         ERR_MSG_CLEANUP("Application of configuration data failed.\n");
     }