in essence, this change switches from CSS icons to <adp:icon> since in default setup (when no themes/icon sets are installed) the CSS based rendering was bad. Using <adp:icon> offers more flexibility and tailorability.
Make adp_parse_ad_conn_file a private interface: its stated purpose is to be registered via rp_register_extension_handler in acs-templating/tcl/acs-integration-init.tcl and it has no practical use otherwise