(re-)add 3rd hardware pwm to be able to shut the output off.
Use saved duty when setting output to "off"
instead of relying on timer duty value.
Use pointers instead of array indices, optimisation.
Rename ambiguous pwm_slot to pwmmeta pointer.
Add power saving support to pwm_timer1
Add fast pck support ("pll") to pwm_timer1.
Cosmetics.
Minor optimisations.