discouraged.h. Replaced all uses with scm_is_pair.
(SCM_I_CONSP): New name for SCM_CONSP.
* pairs.h, pairs.c (scm_is_pair, scm_is_null, scm_car, scm_cdr,
scm_i_chase_pairs, SCM_I_A_PAT, SCM_I_D_PAT, etc, scm_caar,
scm_cadr, etc): New.
(SCM_NULLP, SCM_NNULLP): Moved to discouraged.h. Replaced all
uses with scm_is_null.
(scm_number_p): Export as "number?" to Scheme.
(scm_is_complex, scm_is_number): New.
(scm_c_make_rectangular, scm_c_make_polar): New.
(scm_make_rectangular, scm_make_polar): Use above.
(scm_c_real_part, scm_c_imag_part, scm_c_magnitude, scm_c_angle):
New.
(scm_make_complex): Discouraged by moving to discouraged.h and
discouraged.c. Replaced all uses with scm_c_make_rectangular.
(scm_i_short2big, scm_i_int2big, scm_i_uint2big, scm_i_size2big,
scm_i_ptrdiff2big, scm_i_long_long2big, scm_i_ulong_long2big):
Removed prototypes.
(scm_make_real, scm_num2dbl, scm_float2num, scm_double2num):
Discouraged by moving to discouraged.h and discouraged.c.
Replaced all uses with scm_from_double.
(scm_num2float, scm_num2double): Discouraged by moving prototype
to discouraged.h and rewriting in terms of scm_to_double.
Replaced all uses with scm_to_double.
(scm_to_double): Do not implement in terms of scm_num2dbl, use
explicit code.
(scm_from_double): Do not implement in terms of scm_make_real, use
explicit code.
