Create prov.py
added new methods to add metadata at notebook level, add prov for NIN, changed aoutput prov-key to :  ecoop_prov
adde new notebooks
Merge pull request #11 from epifanio/master

master
Merge branch 'master' of https://github.com/tetherless-world/ecoop
Showed how to capture provenance with ecoop:CodeCellRun