refactor(Core/Tools): remove ACE from tools (#3351)

src/tools/mesh_extractor/ChunkedData.cpp

@@ -66,7 +66,7 @@ Chunk* ChunkedData::GetChunkByName( const std::string& name )
     for (uint32 i = 0; i < Chunks.size(); ++i)
         if (Chunks[i]->Name == name)
             return Chunks[i];
-    return NULL;
+    return nullptr;
 }
 
 ChunkedData::~ChunkedData()