contributions to Messaging and Binding

All,

I spent some time working on Messaging and Binding, primarily on the following:

- Defining the operations $set, $get, $del

- Defining XDI Browser Binding

- and some other minor changes

I created a pull request, so we can discuss before actually merging it into master:
https://github.com/OASIS-XDI-Technical-Committee/xdi-spec-docbook/pull/10

I think it would be good to take a look together on tomorrow's calls..

Markus