Some improvements
Added new hook that gets called when a player tries to change the selection he uses.(Not tested)
Added one function that manages everything when a player tries to select a new point.
Renamed "RegisterCallback" to "RegisterAreaCallback" since there is a new hook.
Fixed warning message.
added end of line.
Fixed another end of line.
Fixed warning when registering hook.
Merge pull request #13 from mc-server/PointSetting

Some improvements