Bug #2882 fix. Clash of detectors with the same Rxy & Phi avoided
update the DB obtain method
missing a comma
StiDetectorBuilder: Added method to remove a previously added Sti detector/volume
StiDetectorBuilder: Modified detector accessor to handle invalid detector requests in somewhat more graceful way
Uniform improvements in Sti objects output streamers
Remove unused variables
Added new data member to keep track of track energy losses in the node