added change to make it easy to run single obsHistID 	modified:   generatePhosimInput.py
added change to make it easy to run single obsHistID
	modified:   generatePhosimInput.py

LSSTDESC/Twinkles,LSSTDESC/Twinkles,rbiswas4/Twinkles,rbiswas4/Twinkles,DarkEnergyScienceCollaboration/Twinkles,DarkEnergyScienceCollaboration/Twinkles