Fixed Some Style Issues

Added: Comments in the main class (QuarterBukkit).
Fixed: Overhauled a comment in the ExceptionHandler class.
Overhauled Installation & Updater

Fixed: The Updater does now actually work with the new versions of QuarterBukkit.
Added: Replaced utility methods with the FileUtils utility class.
Removed: Unnecessary return values from the Updater methods.