Added a few new features: warm-up, cool-down, qt.free permission support and improved checkSafe

+ Added configurable warm-up and cool-down periods (currently global)
+ Play effects and display a countdown message during warm up
+ Cancel warm up if the player leaves the QT region
+ Refactored the cost calculation code, removed duplication between QT
logic and QTList logic
+ Added optional global cost option, qt.free and qt-to-qt costs still
override
+ Changed departure effect to be very slightly different to arrival
effect, uses enderman teleport sound
+ Added qt.instant permission which can be given to players to ignore
warm-up and cool-down timers
+ Added qt.user permission check to player move event handler so that
players who are denied access to qt don't get notifications
+ Removed old checkSafe method and replaced with a simple loop that
encases the player in glass if the target location is in lava