update `hash'

update `hash'

* libguile/hash.c (scm_raw_ihash): Rename from `hasher'.  Remove the
  modulo argument; we expect the caller to deal with that.  Use
  scm_i_hashq for immediates and non-immediate integers.  Use
  scm_raw_ihashq on pointers too.  Update the vector and pairs hashing
  code.  There is still some work to do here.
  (scm_ihashv, scm_ihash): Adapt.