Initial work towards decoupling contact adding

New conf variable in converse.js to indicate how contacts are added (either via
XHR or directly).
Globally rename xmppchat to converse
Add docs directory

And a file with some preliminary notes
Add google analytics
Make converse.js more modular

- Removed the $(document).ready handler. Instead, converse.initialize must be
  called manually together with settings data.
- As a result the Plone specific event listeners are now also gone.
- Update tests and index.html to deal wit these changes
Initialize converse inside main.js
Notes formatting
Fixed auth.

It depended on triggering events for which we've removed the handlers
Fetch the user's vcard when you subscribe to them
Fetch the user's vcard when you subscribe to them
Fix quirks with the add-contact dropdown
Clear connect form fields so that it cannot be resubmitted
Update README and index.html

Now that standalone contact adding works
Merge branch 'master' into gh-pages