add samples lists; drop placeholder
implement dataset.py

Learn more about static datamembers and @classmethod.
I should be able to reuse this for other analyses later on.
import utils.py from SusyTest0
zjets: drop low mass samples (missing from n0145)
diboson: comment out MassiveCB (missing from no145)
top : comment out a few samples (missing/ambigous)
make lists