FPGATrackSim: Implemented use of a layer map to make slice dependent layer assignments

Added code to read a layer map from a JSON file and use it to assign layers after binning. The layer map is set in the python with hooks to set it as a command line flag "Trigger.FPGATrackSim.GenScan.layerMapFile=path/lyrmap.json". The default behavior is unchanged. If the layer map is set then its used.

@wcastigl @jahreda @brosser

Trigger/EFTracking/FPGATrackSim/FPGATrackSimConfTools/python/FPGATrackSimAnalysisConfig.py

@@ -220,6 +220,9 @@ def FPGATrackSimRoadUnionToolGenScanCfg(flags):
     for (cut,val) in cutset.items():
         setattr(tool,cut,val)
 
+    # set layer map
+    tool.layerMapFile = flags.Trigger.FPGATrackSim.GenScan.layerMapFile
+
     # even though we are not actually doing a Union, we need the 
     # RoadUnionTool because mapping is now there
     RoadUnion = CompFactory.FPGATrackSimRoadUnionTool()