More Masteria quests + several minor fixes

Added more quests on Masteria and updated drop data in the region. Fixed
mystic door on slopes deploying players unproperly. Fixed mounts
equipped by low level players crashing the client.

src/tools/MaplePacketCreator.java

@@ -2386,7 +2386,9 @@ public class MaplePacketCreator {
                         }
                 }
                 mplew.write(0); //end of pets
-                if (chr.getMount() != null && chr.getInventory(MapleInventoryType.EQUIPPED).getItem((short) -18) != null) {
+                
+                Item mount;     //mounts can potentially crash the client if the player's level is not properly checked
+                if (chr.getMount() != null && (mount = chr.getInventory(MapleInventoryType.EQUIPPED).getItem((short) -18)) != null && MapleItemInformationProvider.getInstance().getEquipStats(mount.getItemId()).get("reqLevel") <= chr.getLevel()) {
                         mplew.write(chr.getMount().getId()); //mount
                         mplew.writeInt(chr.getMount().getLevel()); //level
                         mplew.writeInt(chr.getMount().getExp()); //exp