Delegate UI to downstream projects

All of `assets/` should be moved downstream to PyritePHP-Example and PyriteView.  This might involve some cleaning up in `src/globals.php` as well.

I have a second project which could benefit from PyritePHP, but it'll be using PureCSS or SemanticUI, not Bootstrap, so PyritePHP should provide the CGI service, sure, but not a sample functional GUI.