EXTENDED TODO
* PCDuino:
    * I2C
    * PWM
    * ADC
* Firmata
    * ADC
    * I2C
* GStreamer
    * all_desc()/pin_desc()
    * Docs
    * Release
* Interrupts
* SPI
* OneWire
* Serial
* Servos (part of PWM in REST interface, but different role)
* Sensors
    * Pressure
    * Luminosity
    * Distance
    * Gyro
    * Accelerometer
    * Moisture
* Wireless communication
    * NRF24L01
