Thread-safe DDValue

* Use TBB containers
* Note: We assume that geometry does not change during one simulation run
better is 
add a std::atomic<unsigned int> m_size =0; to the class;
here
auto result = indexer().insert( std::make_pair( name, 0 ));
if( result.second )  (*result).first.second = m_size++;
id_ = (*result).first.second;