Turn the LED off at the end of the fade sequence

Instead of relying on the active effect to turn the LED off, do so
ourselves at the end.

Fixes #1.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>

src/Akela/LED-Stalker.cpp

@@ -67,8 +67,10 @@ namespace Akela {
             map[r][c] -= 16;
           else if (map[r][c] >= 32)
             map[r][c] -= 32;
-          else
+          else {
             map[r][c] = 0;
+            led_set_crgb_at (r, c, (cRGB){0, 0, 0});
+          }
         }
       }
     }