Bukkit

- New claim system (/bgift claim) to prevent receiving rewards in specific worlds (permission: birthdaygift.claim).
- New claim reminder for players who don't claim their rewards immediately.
- New configurable messages for claim reminder and money received.
- Cleaned up the code a fair bit and reworked some parts.
- Fixed birthdaygift.* permission. It works fine for me. Let me know if it doesn't work for you.