Log files use DATE_RFC3339_EXTENDED

This addresses !7

Log files now use milliseconds in their filename. This should be sufficient for small servers.

index.php

@@ -60,8 +60,11 @@
 		$type = "";
 	}
 
-	//	Create a timestamp in ISO 8601 format for the filename
+	//	Create a timestamp for the filename
-	$timestamp = date( "c" );
+	//	This format has milliseconds, so should avoid logs being overwritten.
+	//	If you have > 1000 requests per second, please use a different server.
+	$timestamp = ( new DateTime() )->format( DATE_RFC3339_EXTENDED );
+
 	//	Filename for the log
 	$filename  = "{$timestamp}{$type}.txt";