User guide revamp

[Simon Laws <si...@googlemail.com>]

While Subversion has been down I've made a start upgrading the user guide to
make it a little more coherent and bring it up to date a little. Big changes
so far are that I've moved the command line walk through out into a separate
guide and I've started replacing some out of date material in the user guide
itself.

I'm making a stab at keeping a single guide relevant to all recent releases.
I think it's useful to explain, for example, why we have host.embedded and
node implementations in one place but I welcome thoughts on that. I'm not
done with the edits yet by a long way but I've run out of time today and
wanted to point out I've started in case people wonder why things are
changing or, more importantly, feel like helping ;-)

Regards

Simon