Made a few changes in example ipython notebook to fix issue
Made a few changes in example ipython notebook to fix issue

- Import of DBConnection changed after the change in catsim
- Instances of user supplied variable name `snid` for indexing SN
  objects changed to `id` following changes to the catsim database
  tables on fatboy
	modified:   examples/reference_lc.ipynb

DarkEnergyScienceCollaboration/Monitor,DarkEnergyScienceCollaboration/Monitor,LSSTDESC/Monitor,LSSTDESC/Monitor