WithdrawPlus

- Added a /givevoucher command to get a voucher signed by the server.

- Use a '%' in commandMessages to seperate multiple lines.

- Added permissions for the commands:

- withdrawplus.withdrawxp: Use the /withdrawxp command.

- withdrawplus.withdrawmoney: Use the /withdrawmoney command.

- withdrawplus.givevoucher: Use the /givevoucher command.

- withdrawplus.*: Use all WithdrawPlus commands