Finished bytevectors Section 2.2: "Operations on Bytes and Octets".

Finished bytevectors Section 2.2: "Operations on Bytes and Octets".

* configure.ac: No longer look for <arpa/inet.h>; look for <byteswap.h>
  and <limits.h>.  No longer look for `htons ()' and friends.

* modules/r6rs/bytevector.scm: Updated exports.
  (endianness): Fixed.

* src/bytevector.c: Include <limits.h> and <byteswap.h>
  (non_native_byteswap_16, non_native_byteswap_32): Fixed.
  (twos_complement): New.
  (bytevector_large_ref): Fixed.
  (bytevector_large_set): New.
  (INTEGER_ACCESSOR_PROLOGUE): New.
  (INTEGER_SET): New.
  (scm_r6rs_bytevector_uint_set_x, scm_r6rs_bytevector_sint_set_x): New.

* tests/bytevector.test: New tests.

git-archimport-id: lcourtes@laas.fr--2006-libre/guile-r6rs-libs--devo--0--patch-1