Move operations and aliasing theorem to separate file.
Parametrize operations by memories instead of memory environments.

Now we have a more clear separation: memory environments are used in typing
judgments and memories in the operational semantics. Also, this makes the
executable semantics a lot faster in some situations because we do not have to
compute the memory environment for any single operation/cast/...
Clean stuff generated by ocamlbuild.
Some integer tests.
Rename block -> local, breakat -> catch.
Force build of ch2o binary.
Do scopes right.
Pretty printer for N and Z, fresh string generator.
Misc tests.
Simplify Undef states.
No more longer "long long"s.
Pretty print char list in OCaml top level.
Remove obsolete OCaml function index.