Add time information to line count statistics

[asharov]

It would be interesting to be able to answer the question "How old is your code?" That is, from the current code base, get statistics of how many lines are from which year, or month, or some period.

This may not be feasible to do. There may be quite a bit of extra processing needed to compute this information, and I'm not sure whether it even is incrementally computable. Also, storing it all will make the database grow quite a bit.