Implement all new functions from 0.8.8 and also wire up missing
functions from previous releases, ie the virStreamPtr functions

* Virt.xs, lib/Sys/Virt.pm, lib/Sys/Virt/Domain.pm,
  lib/Sys/Virt/Domain.pm: New APIs/constants
* lib/Sys/Virt/Error.pm, typemap: Wrapper for stream APIs