Use spaces for intentation

Signed-off-by: Fredrik Lindberg <fli@shapeshifter.se>
Create a base LedStrip class

Move the common pixel functions into a base class and
only led LedStrip_WS2801 deal with the SPI dev. This
allows for a LedStrip_Dummy class for debugging.

Signed-off-by: Fredrik Lindberg <fli@shapeshifter.se>
Add dry-run option with console text output

Allows debugging without leds and only text output
to the console.

Signed-off-by: Fredrik Lindberg <fli@shapeshifter.se>
Automatic brightness adjustment based on sunset/sunrise

Lower the brightness of the LEDs during the night.  Night
is based as the time between sunset and sunrise and the
fade in/fade out follows a guassian function over the time.

There is also a artificially defined night time during
which time the leds are dimmed even more.  The fade in/
fade out during this time follows a bezier curve with
a rapid fade out and a slow fade in.

Signed-off-by: Fredrik Lindberg <fli@shapeshifter.se>