Fix lenient handling of partials resolution
diff --git a/lib/mustache.dart b/lib/mustache.dart
index 163f0bc..2475c68 100644
--- a/lib/mustache.dart
+++ b/lib/mustache.dart
@@ -76,7 +76,7 @@
 
   factory TemplateRenderer(
       PartialResolver partialResolver,
-      {bool lenient,
+      {bool lenient, // FIXME not sure if this lenient works right with the partial resolver, needs to be set twice?
        bool htmlEscapeValues}) = _TemplateRenderer;
   
   String renderString(String templateName, values);
diff --git a/lib/template.dart b/lib/template.dart
index c41f857..aa8a7a8 100644
--- a/lib/template.dart
+++ b/lib/template.dart
@@ -288,8 +288,16 @@
   _renderPartial(_Node node) {

     var partialName = node.value;

     _Template template = _partialResolver(partialName);

-    var renderer = new _Renderer.partial(this, template);

-    renderer.render();

+    if (template != null) {

+      var renderer = new _Renderer.partial(this, template);

+      renderer.render();      

+    } else if (_lenient) {

+      // do nothing

+    } else {

+      throw new MustacheFormatException(

+          'Partial not found: $partialName',

+          _templateName, node.line, node.column);

+    }

   }

 

   static const Map<String,String> _htmlEscapeMap = const {