*Title: Proxy support

*Incentive:
Proxy support needed for "outside data" 
(RSS, link checking, downloading site packages with "setup wizard").

*Documentation:
Proxy support with Proxy authentification has been added to 
linkchek.php, rssimport.php and downloading site packages.

NOTE: You will need CURL compiled with your php installation.

New INI settings in site.ini have been added:

- Added site.ini[ProxySettings].ProxyServer
  Proxy server which will be used
  
  If empty proxy will NOT be used.
  
- Added site.ini[ProxySettings].User 
- Added site.ini[ProxySettings].Password
  For proxy authentification.