added server to access _server safely (without E_NOTICE).
added with method to set post data in request (hack).
fixed for new WebApp class.
renamed Dispatcher to AppChain, because it is a Chain-of-Reponsibility implementation.
added post data as 2nd parameter for page object.
and added dispatch method for future interception?
WebApp also sets $post to itself.
removed old Loader related test; no tests left...
added .html as loadable template page.
added txt, text, and htm, as loadable template files.
added markdown files (.md, .md.php, and .markdown) as loadable files.
added '.txt.php' as loadable file.
code for generating navi-menu for bootstrap. copied from AmidaMVC.