issue17:fix led model memory bug; issue19:header time is not utc bug; issue18:header data-obs\darktime\exposure time fix by shaoli's chart;add new star catalog:C6_50sqdeg_ns.py

2. swith to use "interFlux" in CatalogBase.py,
so now the implementation for number of photons been
shot in Photometric and Spectroscopic are the same
3. Minor config option fix in run_sim.py

fix the crashe when use a filter that is not in the list of run_chips for mag cut. add new feature: add additional output columns to the .cat file, see NGPCatalog.py as an example