Improved timings

This commit will do something like this:

- Scan keyscanning data every 1 second
- When a button is pressed we scan every 0.17 second for 10 seconds
- After 10 seconds we scan again every second

This reduces CPU usage a lot but has the disadvantage you must press at least 1 second on the first button.
Still have to do some trial and error to check if we need better timings.
Improved LED timings

Because of this we no longer need to only blink once. Keeping a button pressed /will/ increase your load though.
SPI/bcm2835 doesn't like to do a spi_transfer() every 0.17s so it seems.