Started working on evaluating embedded blend trees.

src/AnimGraph/AnimGraphBlendTree.cc

@@ -73,7 +73,7 @@ void AnimGraphBlendTree::MarkActiveInputs() {
     }
   }
 
-  for (size_t i = m_eval_ordered_nodes.size() - 1; i > 0; i--) {
+  for (size_t i = m_eval_ordered_nodes.size() - 1; i >= 0; i--) {
     AnimNode* node = m_eval_ordered_nodes[i];
     if (checkIsNodeActive(node)) {
       node->MarkActiveInputs();