Fade LEDs in and out when timer ends.

[jhanarato]

Test Case:

1. Power off and toggles off-on-on.
2. LONG_TIME = 20000, SHORT_TIME = 5000
3. Power on.
4. Switch on toggle 1.
5. LEDs 1, 2 and 3 are all lit.
6. After 20 seconds the timer beeps and
7. The fade in-and-out LED effect happens.
8. Switch off toggle 1.
9. The fade effect ceases and LEDs 2 and 3 are lit.
10. Switch off toggle 2.
11. Switch on toggle 1 (now the toggles are on-off-on)
12. LEDs 1 and 3 are lit.
13. After 5 seconds the beeper beeps.
14. The fade effect is displayed as before.
15. Switch off toggle 1.
16. Fade effect ceases and LEDs 1 and 3 are lit.