Energy Mode 0-4 example.

This example project for the EFM32GG-DK3750 development kit, illustrates the
various energy saving modes of the EFM32GG990F1024.

Use joystick Up and Down to select the demo, after pressing the kit AEM 
button to enable the display to be driven from the Giant Gecko.

When the correct demo has been selected, press PB1 to activate it. 
After this, you need to use the kit's AEM button again to go back to the
energy mesaurement display. A new press on the AEM button will not bring
back the original screen, as the Giant Gecko will be in a sleep mode. You
need to restart to test another demo.

Board:  Silicon Labs EFM32GG-DK3750 Development Kit
Device: EFM32GG990F1024

