Added input scaling function and averaging of multiple readings for
noise reduction to the analogue input node.
Added the ‘sanity check’ read of the digital input pin to the timer
callback in the discrete input node
Mutable/immutable behaviour of breakpoints completed, and the 0 and 1
input values are no longer editable.
Adding a breakpoint now inserts it in the list in next-to-last
place, with sensible default values.
