Fix reset to use system definition of digital write

[ajowsey]

Within init(), reset(1) is called if a hardware reset is provided:
}
if (hardware) {
// Check if bit 2 of REG_MISC is set
// if so nReset will not issue a POR, we'll need to clear that bit first
byte regMisc = readByte(REG_MISC);
if (regMisc & (1 << 2)) {
regMisc &= ~(1 << 2);
writeByte(REG_MISC, regMisc);
}
// Reset the SX1509, the pin is active low
pinMode(pinReset, OUTPUT); // set reset pin as output
digitalWrite(pinReset, LOW); // pull reset pin low
delay(1); // Wait for the pin to settle
digitalWrite(pinReset, HIGH); // pull reset pin back high
}

The bolded lines of code above assume your Arduino will reset the io expander using the gpio assigned to pinReset. Problem is that this library actually calls SX1509::digitalWrite() instead of the Arduino digitalWrite. So the hardware reset never occurs

[nseidle]

Looks good! Thank you.