re #428: Kill off some more WIRIS PHP.

There's still some PHP in use, but it's only used to render the
editor page, now. All requests to 'service.php' now go straight
to the Java Servlet instead of being proxied through PHP as they
were before.

Leaving this for now. The most significant things we should do
when we pick this up next are:

- Destroy the rest of the PHP.
- Move integration bits that don't have anything to do with CKEditor
  to somewhere else so they can righteously use our common code
  (rather than, e.g., the custom AJAX cruft they're doing right now)
  and then inject those dependencies into the plugin.
- Replace the MutationObserver hackery with more more 'sed's or 'awk's
  or such in the WIRIS Rakefile.