Files copied from the step-up project, and slightly modified.

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.