Rewrite docstring in `elts.urls` module.
Install dajaxice.

Modify settings file so dajaxice is available for use. Update README to reflect
that dajaxice should be installed.
Implement simple dajaxice method call.

Use dajaxice to perform a very simple task: when a certain button is clicked,
fetch a message from the server and display it as an alert box. This is a proof
of concept that dajaxice works.