- Todo: merge the repeated ids into a single detector construction if
  possible

	modified:   compact/definitions.xml

This allows for a frame to be defined as the subtraction of 2 trds.

- Implemented using SimpleDiskTracker

- Renamed the vertex and tracker barrel detectors
- Commented out endcap tracker
- Added more detailed to space frame construction.

 - Broke TRD into to planes (per the ref. detector image).

	modified:   compact/vertex_tracker.xml

Fixed ce_GEM overlap

 - CylinderTrackerBarrel_geo can be used to define detailed modules
 which are then placed in barrel array.
 - The modules are cylindrical segments of a tube.
	modified:   compact/definitions.xml
	modified:   compact/gem_tracker_endcap.xml
	new file:   compact/mm_tracker_barrel.xml
	modified:   reference_detector.xml
	new file:   src/CylinderTrackerBarrel_geo.cpp

 - Uses the TrapEndcapTracker geometry construction
 - Material thicknesses needs attention.

 - Vertex tracker endcaps are simple disk trackers.

Dmitry Romanov authored 3 years ago and Whitney Armstrong committed 3 years ago

	modified:   reference_detector.xml

	modified:   compact/definitions.xml
	new file:   compact/forward_romanpot.xml
	modified:   reference_detector.xml

	new file:   compact/B0_tracker.xml
	modified:   compact/definitions.xml
	modified:   reference_detector.xml
	new file:   src/ref_RectangularTracker_geo.cpp

 - Currently just a volume  containing air.