added stack trace log on error

samples/list.noja

@@ -3,4 +3,11 @@
 l = [1, 2, 3, 4];
 
 print('The list contains ', count(l), ' items.\n');
-print('The list is: ', l, '.\n');
+print('The list is: ', l, '.\n');
+
+
+fun fail()
+	assert(false);
+
+
+fail();

samples/webservice.noja

@@ -0,0 +1,10 @@
+
+fun index(req)
+	return {code: 200, 'body': 'Hello, world!'};
+
+routes = {
+	'/': index,
+	'/groups': list_groups
+}
+
+res = serve(8080, routes);