Andrews-Curtis running moved to a separate object. Worksheet created. Strangely need to move baseDistbn for running.
Merge branch 'master' of https://github.com/siddhartha-gadgil/ProvingGround
Crashing of baseDstbn diagnosed and fixed.
Cause: recursively needed to create object Andrews-Curtis, including baseDstbn.
Solution: Made inner vals private instead.
Alternative: Make things lazy.