[Halld-physics] DDetectorMatches in REST

[Paul Mattione]

I've now added the new DDetectorMatches class to the REST file format and checked in the changes to the trunk.  With this change, tracks no longer need to be re-swimmed through the detector when analyzing REST files, because the track <--> shower/hit matching results are saved to file.  This change significantly speeds up analysis time, but increases file size.  There is probably room for improvements, but it's working for now.  

However, since there are still huge holes at the backwards angles in the track reconstruction, I still recommend using the software from the analysis workshop when performing physics studies.  

 - Paul