Moved the SoundManager and the 2D math function (helpers) from the shooter demo to the fife extensions. Fixed fife_timer as it didn't work in the first place. Modified the SoundManager to use the now working fife_timer and removed the Timer class from the shooter demo entirely

<VBox opaque='1'>
	<Button name="moveButton" text="Move here" />
	<Button name="talkButton" text="Talk" />
	<Button name="kickButton" text="Kick" />
	<Button name="inspectButton" text="Inspect" />
</VBox>