When RaspJuice errors it returns 'Fail', it shouldn't always return fail.

[martinohanlon]

Not every api call should return a 'Fail' message in the event of an error but at the moment they all do.

This creates issues when a function which shouldn't return a Fail errors and returns a 'Fail' the next call function call which should return a 'Fail' ends up reading the 'Fail' from the socket buffer and returns as an error even if it was successful.