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

<Window title="Load Map">
	<HBox>
		<VBox>
			<DropDown name="mapList" min_size="100,0" />
			<Spacer />
		</VBox>
		<VBox>
			<Button name="okButton" text="Load Map"/>
			<Button name="closeButton" text="Cancel"/>
		</VBox>
	</HBox>
</Window>