First draft of bindings document

All,

	Here is a rough cut at a first draft of a bindings document. It is
currently missing examples and some connective text and the prose needs
quite a bit of revision but it is a start.

	One issue to consider is that the boundary between the two docs
could be moved in various directions. In particular there is something of an
overlap between the security work an the work arround DoS protection and
asynchrnous messaging capability (i.e. pending status).

	The draft specifies three major bindings, XKMS payload, TLS and
WS-Security. I believe that our current stand is that payload is a MUST, TLS
is a MUST and WS-Security is a SHOULD.

	In addition to the main bindings I introduce the concept of an
implementation, this is because I want to be very precise about certain 'mix
and match' type areas where features may not be necessary or may be handled
in different ways. For example TLS may be used with no client auth at all,
with certificate based client auth or with payload auth. I have given each
of these variants its own individual URI.


		Phill