tests: test more vweb template features

examples/vweb/index.html

@@ -2,3 +2,14 @@ Test <b>app</b>
 <br>
 <h1>@hello</h1>
 <hr>
+@if show
+	show = true
+@end
+
+@for number in numbers
+	@number <br>
+@end
+
+
+<hr>
+End.