Bukkit

Leaned out some codes for better future code management.

Removed the following permissions

• permission: ranker.rankname.rankup:
• permission: ranker.rankname.rankdown:

Added the following permissions

• permission: ranker.rankup:
• description: Change your rank when you rank up. Setting this to false will disable both (rankup) message and command.
• permission: ranker.rankdown:
• description: Change your rank when you rank down. Setting this to false will disable both (rankdown) message and command.

• May add more stats type in future updates