Ocaml oasis

Add OCaml Oasis

OCaml Oasis is a configure/build/install system for OCaml proget (like Cabal for Haskell).

Also add and upgrades other related packages:
- Upgrade Type_conv (needed for oasis)
- Add ocamlmod, ocamlify, odn (needed for oasis)
- Upgrade OCaml react (oasis facilitates its build)
- Upgrade OCaml Batteries (actually unrelated to oasis but a good thing anyway, I suppose)