hpDec fix + Save quest expiration

Fixed an issue that would let a player to delay or anticipate the next
map hpDec proc in certain conditions. Implemented mechanic that enables
the DB save of expiration times for quests that needs this.

sql/db_database.sql

@@ -16433,6 +16433,7 @@ CREATE TABLE IF NOT EXISTS `queststatus` (
   `quest` int(11) NOT NULL DEFAULT '0',
   `status` int(11) NOT NULL DEFAULT '0',
   `time` int(11) NOT NULL DEFAULT '0',
+  `expires` bigint(20) NOT NULL DEFAULT '0',
   `forfeited` int(11) NOT NULL DEFAULT '0',
   `info` tinyint(3) NOT NULL DEFAULT '0',
   PRIMARY KEY (`queststatusid`)