Merge pull request #117 from pamod/mqtt_dev

MQTT changes/perf related, fixing the instance being initialized more th...
executor name removed
bug fixed - messagses do  not receive in direct mode
gave a name to disruptor executor
Merge pull request #118 from sajinidesilva/slots

bug fixed - messagses do not receive in direct mode
Avoid re-sending already sent messages when the channel is closed.
Merge pull request #119 from akalankapagoda/AvoidResend

Avoid re-sending already sent messages when the channel is closed.
Fix for MB-828
Merge pull request #121 from sperera/master

Fix for MB-828
Fixing some of the warnings, made perf related changes, removed deliveredButNotAckedMessages hash map since that map was not used operationally and only put and remove were performed on it and not get
Changes