[HtmlFormat] Revert use of filter_input to $_SERVER
[HtmlFormat] Revert use of filter_input to $_SERVER

https://bugs.php.net/bug.php?id=49184
indicates a verified (not solved) bug where filter_input returns
NULL when used with INPUT_SERVER

ORelio/rss-bridge,sebsauvage/rss-bridge,kranack/rss-bridge,ORelio/rss-bridge,Frenzie/rss-bridge,kranack/rss-bridge,polo2ro/rss-bridge,simonbru/rss-bridge,RSS-Bridge/rss-bridge,Frenzie/rss-bridge,ORelio/rss-bridge,kranack/rss-bridge,teromene/rss-bridge,mro/rss-bridge,Riduidel/rss-bridge,kranack/rss-bridge,teromene/rss-bridge,Riduidel/rss-bridge,Riduidel/rss-bridge,simonbru/rss-bridge,LogMANOriginal/rss-bridge,griffaurel/rss-bridge,LogMANOriginal/rss-bridge,GregThib/rss-bridge,RSS-Bridge/rss-bridge,mro/rss-bridge,RSS-Bridge/rss-bridge