For RedisAscoltatore, have a TrieAscoltatore per subTopic because redis
delivers message per subscription rather than per connection.
Added a test to check. Fails for MQTTAscoltatore until Mosca is fixed.
Default options to {} instead of undefined
Tidy up test expression
Fix travis build (istanbul doesn't like circular links)
Fixed indentation line.
Better ignoring of for git and npm.