Created class DetectorPaddle which contains all of the geometry data for a single rectangular paddle detector.
Created class DetectorSector which is used for hit detection optimization.  If a track does not intersect with the face contained in  a DetectorSector,  then the track also does not intersect with any detector paddles in that sector.
Reworked CLASFTOFDetector to make use of the new chanages in  CLASDetectorGeometry, DetectorPaddle, and DetectorSector. Attempted to prevent methods from returning null values.