Change simulate_ucn to take a run number argument
Change simulate_ucn to take a run number argument

-- By default it will still just take the first run in the master config file, but now you can specify on the command line which run to simulate. 
-- Also put the lines involved in running the simulation into a separate function 
mjrasobarnett/ucnsim,mjrasobarnett/ucnsim,mjrasobarnett/ucnsim