Added support for generating the docs using dox-fundation

References #19.
Moved the content of index.js to lib/ascoltatori.js. Added docs to some classes.

The classes doxxed are: AbstractAscoltatore, MemoryAscolatore,
ascoltatori and SubsCounter.

References #19.
Removed the ZMQ 2 dependency for travis.
Switched from 'on' to 'once' for some AMQP events.
Completed the docs for all the modules.

References #19.
Published the docs.

Closes #19.
Fixed auto-publishing of docs.
Added debug to all ascoltatori.

Closes #18.
Handled keepalive for MQTTAscoltatore.

Closes #22.
Added PrefixAscolatore

PrefixAscoltatore is a decorator to publish messages on an ascoltatore
with a prefix.

Closes #21.
Linted everything.

Closes #24.
Added a factory method for all ascoltatori.

Closes #23.
Some more fixes in the README.md
Bumped version to 0.2.0.
Fixed docs publishing.
Added more options in the doc for RedisAscoltatore.
Fixed the automatic publishing of the docs, again.
Rewritten the debug flags so that it does not use the '-' anymore.
More fixed for debugging in the README.md
Bumped version to 0.2.1.