Add max, min, and abs.#11

Merged

jrevels merged 2 commits intoJuliaDiff:masterfrom

willtebbutt:more-diffrules

Mar 14, 2018

Commits on Mar 3, 2018

Add max, min, and abs.
willtebbutt
committed

Commits on Mar 4, 2018

Change abs implementation to use signbit.
willtebbutt
committed