Added a DA->SIXDA check, and a warning message. Improved the run_prepro flow a bit.
Added a DA->SIXDA check, and a warning message. Improved the run_prepro flow a bit.

SixTrack/SixTrack,SixTrack/SixTrack,SixTrack/SixTrack,SixTrack/SixTrack,SixTrack/SixTrack,SixTrack/SixTrack