Improved class_table and feature_table and added assertion_table so that the first proofs can be started

	modified:   library/kernel/boolean.e
	new file:   ocaml/assertion_table.ml
	new file:   ocaml/assertion_table.mli
	modified:   ocaml/class_table.ml
	modified:   ocaml/class_table.mli
	modified:   ocaml/container.ml
	modified:   ocaml/eiffelc.ml
	modified:   ocaml/feature_table.ml
	modified:   ocaml/feature_table.mli
	modified:   ocaml/proof.ml
	modified:   ocaml/support.ml
	modified:   ocaml/term.ml
	modified:   ocaml/type.ml
	modified:   ocaml/verify.ml