Merge pull request #19 from Damme/patch-1

Added MQTTGateway version 0.1b
Merge pull request #20 from Damme/patch-1

Little better readme...
Merge pull request #21 from Damme/patch-1

Minor changes + Added back LED-blinking code.
New example skecth which controls a lock either from controller or by using a secret knock.
Merge branch 'development' of https://github.com/mysensors/Arduino into development
Updated comments
Comment fixed
Move routing message part to the top of message to ease later refactoring of header/payload (encryption etc).
Fix error and add chirp when correct code entered.
Fix indentation.
UV sensor example added
Fix spelling error
Add Custom sensor type that can be used in presentation when no other sensor fits.
Dust sensor added. Thanks epierre.
Removed a few decimals from pressure value.
Serial protocol changed to allowing controller to know if an incoming message is a ack. Outgoing and incoming serial messages now also have the same parameter count.

radioId;childId;messageType;ack;subType;payload\n

Where ack parameter means the following:
outgoing: 0 = unacknoledged message,  1 = request ack from destination node
Incoming:  0= normal message, 1=This is an ack message
Merge pull request #22 from Damme/patch-1

Changed from Switch/case to if/elseif to save some runtime ram
Merge pull request #23 from Damme/patch-1

moved comment and minor ops
Add emon lib for a later non invasive current sensor.
Added a new RFID Lock Sensor example.