Wrapped "puback" call in a try-cactch for node v0.10.
Updated ascoltatori to safe node 0.10 branch.
Updated MQTT.js to v0.2.6.
Update zmq to v2.4.0.
Merge branch 'master' into node-v0.10

Conflicts:
	lib/server.js
	package.json
Added node v0.10 into travis.
Updated ascoltatori to v0.4.1.
Merge branch 'node-v0.10'
Fixed node v0.10 support for in the authentication system.

References #20.