o make it be 'use strict' aware
  o factorize options managment in one place
- standalone tools :
  o they all now support -h|--help -v|--version, ...
  o they can add their own options to %standalone::usages
- harddrake : use std --testing/$::testing rather than its own
  --test option

rationale:

- currently, we use _("xxx") as a shorthand for gettext("xxx"). It
also used to call xgettext with --keyword=_

- alas, function &_ is global and not by package (notice esp. that _
is not exported in common.pm)

- this lead to big ugly pb with packages defining their own &_,
overriding common.pm's &_

- a fix is to set @::textdomains to add a new domain (the default
being "libDrakX")

but relying on the global "_" is still dangerous!

  with nice help from Pixel for the tough Perl part
- move 'use standalone' up in all standalone apps,
  to comply to 'explanations'