Improve favicon detection

lib/utils.php

@@ -47,6 +47,11 @@ class OC_News_Utils {
 
 		if ($favicon == null) {
 			//handle favicon detection
+			$favicon = SimplePie_Misc::absolutize_url('/favicon.ico', $url);
+
+			// FIXME check if file exists and is valid
+			if (false === file_get_contents($favicon, 0, null, 0, 1))
+				$favicon = null;
 		}
 
 		$feed->setFavicon($favicon);