Rebuild samples

Updates!

* hello-world, server-with-links, ring-middleware were straightforward.
* template server pages now produce identical html and have been updated to recent versions
* cors sample was completely overhauled.

With the exception of `hello-world`, changed all of the `main` functions to follow this structure:

```clojure
(-> service/service
    server/create-server
    server/start))
````

Other stuff:

* Removed `dev` clutter; we should consider adding a sample focused around actual development 
work processes, but with dev scattered about, each sample loses focus.
* Moved source files, templates, static files, etc. into `resources/` directories.
* Updated documentation where required.
Did you remove this stuff, or is it not present in the template?  I think the template comments should be preserved in the samples.  People take this sample code and use it as the foundation for their applications.  If we remove these comments, and they never generate a project from the template themselves, they'll never know about these settings.