Spark

Spark.io support
- The shortened indent needs to be restored
- I wonder if `core-firmware` would accept a patch to change [this](https://github.com/spark/core-firmware/blob/b64f938beb24a2d873058d9724f6f5f51cc8ecd5/src/spark_wiring.cpp#L210-L218) to this: 
```c
if (value == LOW)
{
  PIN_MAP[pin].gpio_peripheral->BRR = PIN_MAP[pin].gpio_pin;
} else 
{
  PIN_MAP[pin].gpio_peripheral->BSRR = PIN_MAP[pin].gpio_pin; 
}
```
That would allow this changeset to be reverted. I've filed this bug: https://github.com/spark/core-firmware/issues/247