JSON-XD now renamed JXD

Just a note that I did my action item from today's meeting and updated the https://wiki.oasis-open.org/xdi/JsonXdiMapping page to reflect our decisions about "the format formerly known as JSON-XD". 

It's now JXD. I also updated the examples. I'm looking forward now to driving into the details of defining the format we have always needed to make XDI accessible to developers.

=Drummond