Editing EPrints 3.4.3 (section)

==== Summary of Changes ====
* All existing URL and path configuration settings have been retained to ensure existing plugins and bespoke code continue to function.
* Eliminated use of <code>http_url</code> (except in Apache configuration generation), <code>https_url</code>, <code>http_cgiurl</code> and <code>https_cgiurl</code>.
* Used <code>base_url</code> and <code>perl_url</code> for links related to user-generated content (i.e. eprint summary/abstract pages, document download URLs, document preview images/thumbnails, etc.), links defined in the head of a web page that are not directly related to the generation of the page (i.e. everything but CSS stylesheets, JavaScript and favicons) and links that are rendered as text on a web page.  
* Used <code>rel_path</code> and <code>rel_cgipath</code> for all other purposes where it is unnecessary to use <code>base_url</code> or <code>perl_url</code>.
* Eliminated use of <code>http_cgiroot</code> and <code>https_cgiroot</code> and limited use of <code>http_root</code> and <code>https_root</code> to Apache configuration generation and in defining other configuration settings.
* Ensured <code>rel_path</code> and <code>rel_cgipath</code> are used for links in templates, static pages and other places where previously no URL/path configuration setting was used.  To ensure these links work when EPrints is not running on the root path (i.e. <code>rel_path</code> is not an empty string).