USB_Init() no longer calls sei() to enable global interrupts - this must now be done in the user application once all init code has run.

Demos/Device/Incomplete/Sideshow/Sideshow.c

@@ -58,6 +58,7 @@ int main(void)
 	SetupHardware();
 
 	LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
+	sei();
 	
 	for (;;)
 	{

Demos/Device/Incomplete/Sideshow/Sideshow.h

@@ -35,6 +35,7 @@
 		#include <avr/io.h>
 		#include <avr/wdt.h>
 		#include <avr/power.h>
+		#include <avr/interrupt.h>
 
 		#include "Descriptors.h"
 		#include "Lib/SideshowCommands.h"