Lookup module references (more) lazily

ref: #44. Only keep the children instead of re-binding the module reference,
which could result in premature Lazy.force
Fix ocp-build args
version 1.0.3
Fix: prefix of opened values were shadowed
Start of a new version of ocp-browser, using LambdaTerm.
Show result of a query (without colors for now).
fixup build system.
Add a completion engine.
Various bug fixes

- Handle Pervasives namespace correctly
- Better handling of exit and completion bindings.
Implement colors.
Small cleanup and doc.
Mark the current selection.
Simplify significantly the show_bow widget.
Simplify slightly completion printing.
Some documentation.
Add kind annotation (with colors !)
Small clean up.
Disable warning 40.
enable ocp-lamdba in opam package.
Module movement with alt + arrows.