(scm_tc16_enclosed_array, SCM_ENCLOSED_ARRAYP):

(scm_tc16_enclosed_array, SCM_ENCLOSED_ARRAYP):
New.
(exactly_one_third, singp): Removed.
(scm_array_p, scm_array_dimensions, scm_shared_array_root,
scm_shared_array_offset, scm_shared_array_increments): Handle
enclosed arrays explicitely.
(scm_array_rank): Likewise. Also, do not return zero for
non-arrays, signal an error instead since arrays with rank zero do
exist.
(scm_i_make_ra): New, for specifying the tag of the new array.
(scm_make_enclosed_array): Use it.
(scm_make_ra): Reimplemented in terms of scm_i_make_ra.
(scm_make_shared_array): Use scm_c_generalized_vector_length
instead of scm_uniform_vector_length.
(scm_array_in_bounds_p): Rewritten to be much cleaner.
(scm_i_cvref): New, doing the job of scm_cvref.
(scm_cvref): Use scm_i_cvref.
(scm_array_ref): Do not accept non-arrays when no indices are
given. Use scm_i_cvref to do the actual access.
("uniform-array-set1"): Do not register.
(scm_array_set_x, scm_uniform_array_read_x,
scm_uniform_array_write): Handle enclosed arrays explicitly.
(ra2l): Use scm_i_cvref instead of scm_uniform_vector_ref to also
handle enclosed arrays.
(scm_array_to_list): Handle enclosed arrays explicitly.
(rapr1): Removed.
(scm_i_print_array_dimension): Use scm_i_cvref to also handle
enclosed arrays.
(scm_i_print_enclosed_array): New.
(tag_proto_table, tag_creator_table): Renamed former to latter.
Added "a" and "b" for strings and bitvectors, resp.
(scm_i_tag_to_prototype, scm_i_tag_to_creator): Renamed former to
latter.  Tag "a" is in the table now, no need to handle it as a
legacy tag.
(scm_raprin1): Just call scm_iprin1.
(scm_array_creator, scm_array_prototype): Handle enclosed arrays
explicitly.
(scm_init_unif): Initialize scm_tc16_enclosed_array smob.
Use scm_i_print_array as printer for scm_tc16_array.