[sugar] Activity versioning schema

[Michael Stone]

> Otherwise how can we reasonable sort/group the activities in any way
> that makes sense?

I suggested one (stupidly slow, but very general) approach based on the
Travelling Salesman problem. To recap:

Regard all activities as nodes in a fully connected graph. Let
activities state that they are close to some collection of other
activities according to any system you please. (e.g. specify a metric on
activities, plug in some heuristics on names and numbers, give a list of
'similar' activities, do cosine similarity on keyword vectors, etc.)

When you learn that A thinks it should be close to B, shorten the edge
between A and B. 

"Solve" the TSP for the graph. Approximate solutions are fine.

Designate a starting point (I suggest a 'Help' activity) and order your
activities according to your solution. You can even do fancy grouping
tricks for small-diameter subgraphs.

Michael