v5.3.0

• You can now specify autoConnect: false as an option to var socket = socketCluster.connect(options) - If it is false, the socket will not start connecting to the server until you invoke socket.connect() explicitly.
• Added a new 'connecting' event which gets triggered whenever the socket starts connecting to the server - This includes reconnects. Note that if you want to capture the very first 'connecting' event, you will need to set autoConnect to false and register your event handler before you call socket.connect().