moving file descriptor passing into a header

[James McKaskill]

So this fd transferring is a bit a new to me. I suppose the idea is
that returns can then indicate a channel for further transfer of data.
IMHO using an fd as an int as the means of doing this indirection is
heavily unportable (it requires that you are on the same unix system
as the remote - I don't see this idea ever working on windows, and it
also doesn't work if the remote is on a different machine). Why not
instead use a similar system as the object path. IE give the
indirection via a string with a special type that has the port/host to
connect to (ie an address string like "tcp:host=foobar,port=...").
This is actually very similar to how ftp does indirection for data
channels with passive mode.

The dbus wrapper can then notice the special type and open it up for
the user to use  in whatever fashion makes sense for the environment
(ie QIODevice, fd, HANDLE, etc).

James