Infinite testing notebooks

[Avni2000]

Theoretically we can automate the process of:

1. Finding a git repo on github with a permissive license AND lots of different branches/contributors for a few jupyter notebooks spanning a while (rich git history)
2. Create as many conflicts as possible between all branches, between all commits
3. Find how many unmatched cells appear (which aren't "new")
4. Free benchmark for our cell matching algorithm!

[Avni2000]

Relevant to #78