fixed config loading for auth plugins
reformatted lib/exe/fetch.php
run main code only for non-tests in lib/exe/fetch.php
better HTTPClient debug output on CLI
added another HTTPClient test
HTTPClient: fixed max_bodysize when using keep-alive
HTTPClient: updated function comments
HTTPclient: print number of received bytes on error
test for media downloading (related to FS#2675
don't use keep-alive with single shot HTTP clients
don't expose version in info plugin FS#2701
do not expose version in outgoing mails FS#2701
allow richer email addresses in notify and registernotify FS#2689

This deprecates the "richemail" config class
fixed media upload not working with QuickPHP (FS#2531 + FS#2673)
initialize link wizard with current namespace FS#2683
fixed edit toolbar being cut off (FS#2715)
removed useless css from config manager (causing issues in Opera, FS#2678)
added explaining text to _dummy files (fixes issues with some archivers, FS#2616)
moved rewrite rules to uncomment together (FS#2484)
introduced http_status() for sending HTTP status code FS#1698

It seems, some servers require a special Status: header for sending the
HTTP status code from PHP (F)CGI to the server. This patch introduces a
new function (adopted from CodeIgniter) for simplifying the status
handling.