Common routes

[thoughtgap]

1. Walk through the list of most commonly visited places
2. For each place, find the most common next place visited after
3. Store this as a "Common Trip"
4. From there, can easily pick up all the path items in each trip between those two places
5. Trim and discard outlier trips, based on something like meanTripDuration + 2sd

Originally posted by @sobri909 in #20 (comment)