Tiger's UNIX part

in order to accomodate so many new features, the UNIX layer in Tiger had to be seriously upgraded... here are some news:
- new 100% 64 bits kernel with better SMP support.
- the 64 bits kernel allows to use 16 exabytes of RAm (17 179 869 184 gigaoctets)
- new permission management system, allows to affiliate a number of users to the same resource, which removes the limitations of groups
- Launchd allows to centralize all network services running on Tiger
- integration of SQLite and better support of XML on the command line
- Support of file resources in standard UNIX command like tar, cp, nsync