events processing changed: treat events chronologically (except for the first time, to avoid looping throug all history), phpdoc, custom update period

example.php

@@ -25,6 +25,7 @@ $cb = function($event)
 $m = new MatrixClient("https://domain.tld");
 //$m->login_with_password("@bot:domain.tld", "password");
 //echo $m->get_access_token() . "\n";
+$m->set_update_period(0.5);
 $m->login_with_token("@bot:domain.tld", "token");
 $room = $m->join_room("!roomname:domain.tld");
 //$room->send_text("pouet");