Implemented and tested for both platforms. This is quite a big
commit. Unlike with the previous changes to now choosable PWM
frequencies, all board configuration files and Configtool had
to be changed immediately to deal with the additional parameter
in DEFINE_HEATER() and keep AVR builds working (and regression
tests passing).
That is, buttons and choices. Coices apparently don't work. Tried
a bit on the table heaters of the sensor and heater lists, but
found nothing which would result in an effect. This control is
not exactly well documented.
Markus Hitter
jbernardis