DNS XRD Discovery proposal

[Peter Davis <peter.davis@neustar.biz>]

I've finally gotten around to adding to the wiki my suggestions on the  
use of the DNS for XRD discovery [1].

I did not get all the example URIs in that i wanted, but thought,  
given recent conversation, i should at least demonstrate how DNS would  
provide XRD (and site-meta), and perhaps simplify the XRD location  
processing a bit.

=peterd

[1] http://wiki.oasis-open.org/xri/XrdOne/DNSResolution