Sparky handle pwm input and adc on outport

This allows for the following configurations on sparky's "output" port:

PWM10 - all pins used for PWM output
PWM7+3ADC - pins 1 to 7 used for PWM output, pins 8 to 10 used for ADC input. ****
PWM8+2ADC - pins 1 to 8 used for PWM output, pins 9 and 10 used for ADC input.
PWM9+PWM_IN - pins 1 to 9 used for PWM output, pin 10 used for PWM input ***
PWM7+PWM_IN+2ADC - pins 1 to 7 used for PWM output, pin 8 used for PWM input, pins 9 and 10 used for ADC input. ***

**** - if using pin 8 for ADC input an external current limiting resistor must be used.
***  - usefull for systems like FrSky which are able of PPM commands and PWM RSSI.