Removed tell-player-on-powerup option
Updated main to reflect package name change

Changed version to 1.4 and added BukkitDev link for website
Complete redesign of KillStreak plugin

Added new KillStreakChatManager to tidy up chat management
Improved KillStreakManager to increase efficiency
Recreated KillStreakCommandExecutor from scratch to simplify it
Simplified KillStreakEventListener
Updated KillStreakPlugin to reflect these changes