Drop down options for all 17 pins in WiringPi
pintable + tablepin maps for all 17 WiringPi pins
Update to fs.watch node to use new fs.notify API 
requires npm update fs.notify
Update MQTT node Icon color to be different from Twitter one
Fixes #132
Guard against null client in MQTT nodes
Fixes #130

There was a timing window where a client could connect to a broker just as new flows were deployed that would cause the on-connect callback to be called after client has been set to null. This caused an NPE.

The fix is to check client isn't null in the event handler.
Handle duplicate PUBREL
Fixes #138

If the connection to a broker is lost mid qos 2 flow, there is a window where we have processed the PUBREL, released the message and deleted it from our store, but not sent the PUBCOMP. When the connection is re-established, and the PUBREL is resent by the broker, we assume the message still exists - and hit the error reported.

The fix is to check the message is valid before trying to process it. We send the PUBCOMP to complete the flow regardless.
Merge pull request #133 from cpswan/master

Enable Pi to use of all 17 WiringPi pins
enhance labels for Pi GPIO pins
enhance fs.notify help text
windows paths need double slashes \\
Add extra labels to extra Pi GPIO pins