WIP

Implemented features:

# Initialization: Takes a hash with configuration.
led_red   = Machine::GPIO.new({pin: 38, mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
led_blue  = Machine::GPIO.new({pin: 36, mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})
led_green = Machine::GPIO.new({pin: 39, mode: Machine::GPIO::OUTPUT_OD, init: Machine::GPIO::ON})

led_red.value # Get LED pin input value
led_red.value = Machine::GPIO::OFF # Turn on the LED (Level is reversed)
led_red.off # Same as above
led_red.on # Turn off the LED (Level is reversed)
led_red.toggle # Toggle output