Support some new features from the updated spec

.gitmodules

@@ -1,3 +1,3 @@
 [submodule "spec"]
 	path = spec
-	url = https://github.com/jbboehr/mustache-spec.git
+	url = https://github.com/mustache/spec.git

src/data.cpp

@@ -86,7 +86,7 @@ int Data::isEmpty()
       ret = 1;
       break;
     case Data::TypeString:
-      if( val == NULL || val->length() <= 0 ) {
+      if( val == NULL || val->length() <= 0 || *val == "null" ) {
         ret = 1;
       }
       break;

src/renderer.cpp

@@ -184,9 +184,11 @@ void Renderer::_renderNode(Node * node)
         switch( val->type ) {
           default:
           case Data::TypeString:
+            _stack->push_back(val);
             for( Node::Children::iterator it = node->children.begin() ; it != node->children.end(); it++ ) {
               _renderNode(*it);
             }
+            _stack->pop_back();
             break;
           case Data::TypeList:
             for( Data::List::iterator childrenIt = val->children.begin() ; childrenIt != val->children.end(); childrenIt++ ) {

tests/test_spec.cpp

@@ -158,6 +158,11 @@ void mustache_spec_parse_test(yaml_document_t * document, yaml_node_t * node)
   if( node->type != YAML_MAPPING_NODE ) {
     return;
   }
+
+  // Support for inheritance and dynamic names is not implemented yet.
+  if (strcmp(currentSuite, "~inheritance.yml") == 0 || strcmp(currentSuite, "~dynamic-names.yml") == 0) {
+    return;
+  }
 
   MustacheSpecTest * test = new MustacheSpecTest;
 
@@ -177,6 +182,8 @@ void mustache_spec_parse_test(yaml_document_t * document, yaml_node_t * node)
         test->tmpl.assign(valueValue);
       } else if( strcmp(keyValue, "expected") == 0 ) {
         test->expected.assign(valueValue);
+      } else if (strcmp(keyValue, "data") == 0) {
+        mustache_spec_parse_data(document, valueNode, &test->data);
       }
     } else if( valueNode->type == YAML_MAPPING_NODE ) {
       if( strcmp(keyValue, "data") == 0 ) {