never Serial.print (except verbose)

There were quite a few places we were printing direct to serial and those commands wouldn't work via hq, this catches all those cases.

As a result of this change:
*  `pin.status` table format is converted to json as a result, [example output](https://gist.github.com/quartzjer/ec1a750285b31e1e0aa8)
* any `sp(float,precision)` will now print out the float properly
* a `power.volts` script command was added that prints the float value of the voltage