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.
Coerce the currentState to always be numeric & use === tests
Catch the first spurious interrupt when x.value is undefined
Add more debug output
Add a second timer to get the first message out. This still fails at
node-RED startup when the node is not activeLow
Further attempts to get the initial message working. Added activeLow
property. Output messages now include topic. Better help text. Change
name to discrete-in
