interpret hex sequences in ssid station names

resolves #917

includes/functions.php

@@ -641,3 +641,10 @@ function validate_host($host) {
   return preg_match('/^([a-z\d](-*[a-z\d])*)(\.([a-z\d](-*[a-z\d])*))*$/i', $host);
 }
 
+function evalHexSequence($string) {
+    $evaluator = function ($input) {
+	return hex2bin($input[1]);
+    };
+    return preg_replace_callback('/\\\x(..)/', $evaluator, $string);
+}
+

includes/wifi_functions.php

@@ -75,6 +75,7 @@ function nearbyWifiStations(&$networks, $cached = true)
         }
 
         $ssid = trim($arrNetwork[4]);
+        $ssid = evalHexSequence($ssid);
         // filter SSID string: anything invisible in 7bit ASCII or quotes -> ignore network
         if (preg_match('[\x00-\x1f\x7f-\xff\'\`\´\"]', $ssid)) {
             continue;