Map chair skill + Hired Merchant fix

Changed map chair bonus healing mechanic to be a player skill, instead of promptly available for all players (healing buff takes place only if the player has the skill). Hired Merchant now properly checks for a space on the inventory before permitting a player to buy an item/bundle. Minor fix with concurrency on MapleStorage.

src/net/server/channel/handlers/NPCTalkHandler.java

@@ -33,6 +33,7 @@ import tools.MaplePacketCreator;
 import tools.data.input.SeekableLittleEndianAccessor;
 
 public final class NPCTalkHandler extends AbstractMaplePacketHandler {
+    @Override
     public final void handlePacket(SeekableLittleEndianAccessor slea, MapleClient c) {
         if (!c.getPlayer().isAlive()) {
             c.announce(MaplePacketCreator.enableActions());