We use on/off for patterns, so I have rewritten the pattern handling,
removing the pattern_t type altogether, and changed it to use
binary strings of data instead. This uses less RAM for pattern definitions.

I have also changed blink_pattern to include morse code text
(generated by morse.pl), with kids' names.

 especially if it merges an updated upstream into a topic branch.

This does not compile yet, to be fixed.

This will allow us to use power-down sleep when neither ADC nor PWM
is used.

Simplify it as much as possible - single PWM channel only, no
sub-LSB PWM value.

from http://www.fi.muni.cz/~kas/bike-lights/ Git repository as of
commit c30006aaf666f7cff3a6ab949c613c2f8cc6163b

So far two PWM channels OC1A/OC1B with sub-LSB resolution possible
(but unused yet) using timer IRQ.

TODO: get rid of OCR1C register and let it count to 255.