New Sundials package.

Hello,

Would you please accept this package for a new OCaml library?

This is our first opam package, so any suggestions for improvement are welcome.

BTW, This package requires that Sundials 2.5.0 be installed (per http://inria-parkas.github.io/sundialsml/#install). How will that work with Travis?

We will announce our release after the package is published.

Tim and Jun.