First version of a module table included

The module table stores the dependencies between the modules.

	modified:   ocaml/context.ml
	modified:   ocaml/context.mli
	modified:   ocaml/eiffelc.ml
	new file:   ocaml/module_table.ml
	new file:   ocaml/module_table.mli
Commented out calls to printf

	modified:   ocaml/typer.ml
Added the function 'has' to map_table.ml

	modified:   ocaml/map_table.ml
	modified:   ocaml/map_table.mli