Adding a value for reuse of showers

Instead of leaving shower_reuse as Nan, we set it to 1, because the number of showers in the MAGIC root file already include the shower's reuses, but further analysis step (e.g. pyIRF) may want to use the "reuse" value.

ctapipe_io_magic/__init__.py

@@ -336,6 +336,7 @@ class MAGICEventSource(EventSource):
             else:
                 assert self.current_run['data'].mcheader_data['M1'] == self.current_run['data'].mcheader_data['M2'], "Simulation configurations are different for M1 and M2 !!!"
                 data.mcheader.num_showers = self.current_run['data'].mcheader_data['M1']['sim_nevents']
+                data.mcheader.shower_reuse = self.current_run['data'].mcheader_data['M1']['sim_reuse']
                 data.mcheader.energy_range_min = (self.current_run['data'].mcheader_data['M1']['sim_emin']).to(u.TeV) # GeV->TeV
                 data.mcheader.energy_range_max = (self.current_run['data'].mcheader_data['M1']['sim_emax']).to(u.TeV) # GeV->TeV
                 data.mcheader.spectral_index = self.current_run['data'].mcheader_data['M1']['sim_eslope']
@@ -520,6 +521,7 @@ class MAGICEventSource(EventSource):
              #fdp (mono version not fully tested)
             else:
                 data.mcheader.num_showers = self.current_run['data'].mcheader_data[telescope]['sim_nevents'] # total, including reuse
+                data.mcheader.shower_reuse = self.current_run['data'].mcheader_data[telescope]['sim_reuse']
                 data.mcheader.energy_range_min = (self.current_run['data'].mcheader_data[telescope]['sim_emin']).to(u.TeV) # GeV->TeV
                 data.mcheader.energy_range_max = (self.current_run['data'].mcheader_data[telescope]['sim_emax']).to(u.TeV) # GeV->TeV
                 data.mcheader.spectral_index = self.current_run['data'].mcheader_data[telescope]['sim_eslope'] 
@@ -1034,6 +1036,7 @@ class MarsRun:
             if is_mc:
                 mc_header_info = input_file['RunHeaders'].arrays(mcheader_list)
                 mcheader_data['sim_nevents']=int(mc_header_info[b'MMcRunHeader.fNumEvents'][0]) #std: 5000
+                mcheader_data['sim_reuse']= 1 #this value is not written in the magic root file, but since the sim_events already include shower reuse we artificially set it to 1 (actually every shower reused 5 times for std MAGIC MC)
                 mcheader_data['sim_emin']=mc_header_info[b'MMcCorsikaRunHeader.fELowLim'][0]*u.GeV
                 mcheader_data['sim_emax']=mc_header_info[b'MMcCorsikaRunHeader.fEUppLim'][0]*u.GeV
                 mcheader_data['sim_eslope']=mc_header_info[b'MMcCorsikaRunHeader.fSlopeSpec'][0] #std: -1.6