The Caml Hump: Enhtop

This is an experimental patch (we also provide pre-built testing executable and Debian package) for an enhanced OCaml toplevel with additional features. For any kind of bindings (i.e. value, type, module, class etc.): Identifiers been rebound are shown differently by default, to distinguish with currently effective ones; a new directive to query (by kinds or names or their composition) and show both current and history bindings; a new directive to show the current binding of any identifier without evaluating or rebinding it; a type-check-only testing mode to experiment your definitions without polluting the world, and the directive to enter/leave it.