ekmett/intervals — pull request #2 by byorgey (2013-07-01 11:08:07+00:00)
Title: bug fix for `abs`

I could just be misunderstanding something, but if you take the absolute value of a quantity on the interval [a,b] with a < 0 < b, then you get a quantity on the interval [0, max (-a) b], not [max (-a) b, b].