* eval.c, procs.c, procs.h, procprop.c: Renamed getter ->

* eval.c, procs.c, procs.h, procprop.c: Renamed getter ->
procedure throughout.
* procs.c (scm_procedure, scm_setter): Handle entity and operator
setter slots.
* procs.c, procs.h (SCM_PROCEDURE_WITH_SETTER_P, SCM_GETTER,
SCM_SETTER): New macros.
(scm_procedure_with_setter_p, scm_make_procedure_with_setter,
scm_getter, scm_setter): New procedures.
* procprop.c (scm_i_procedure_arity), procs.c (scm_thunk_p): Added
entry for scm_tc7_pws.
* procs.c (scm_procedure_p): Added case label for scm_tc7_pws.