Added some functions

	modified:   ocaml/term.ml
Added 'proof_table.ml'

	new file:   ocaml/proof_table.ml
	new file:   ocaml/proof_table.mli
Added 'fold_with_level' to 'term.ml'

Sometimes it is necessary to know the level from the root node
while folding the free variables of a term (e.g. to see if an
operation has been distributed over some other i.e. if the
operation appears on a deeper level than before)

	modified:   ocaml/term.ml
Added 'equal_wo_names' to 'term.ml'

	modified:   ocaml/term.ml