fix warning

Author: facontidavide

src/controls/reactive_fallback.cpp

@@ -28,7 +28,7 @@ NodeStatus ReactiveFallback::tick()
         {
             case NodeStatus::RUNNING:
             {
-                for(int i=index+1; i < childrenCount(); i++)
+                for(size_t i=index+1; i < childrenCount(); i++)
                 {
                     haltChild(i);
                 }

src/controls/reactive_sequence.cpp

@@ -31,7 +31,7 @@ NodeStatus ReactiveSequence::tick()
             {
                 running_count++;
 
-                for(int i=index+1; i < childrenCount(); i++)
+                for(size_t i=index+1; i < childrenCount(); i++)
                 {
                     haltChild(i);
                 }

src/controls/sequence_star_node.cpp

@@ -43,7 +43,7 @@ NodeStatus SequenceStarNode::tick()
             case NodeStatus::FAILURE:
             {
                 // DO NOT reset current_child_idx_ on failure
-                for(int i=current_child_idx_; i < childrenCount(); i++)
+                for(size_t i=current_child_idx_; i < childrenCount(); i++)
                 {
                     haltChild(i);
                 }