Potential fix for SslHandler dead lock

- Related with: #1181
[maven-release-plugin] prepare release netty-3.6.4.Final
[maven-release-plugin] prepare for next development iteration
Fix a bug in AbstractTrafficShapingHandler.getTimeToWait() where it doesn't work OK when system time goes back.
[#1246] Fix cpu-spinning regression in HashedWheelTimer

Also remove the usage of System.currentTimeMillis() completely here to make it more consistent and correct
[#1246] Correctly convert to nanos
[maven-release-plugin] prepare release netty-3.6.5.Final
[maven-release-plugin] prepare for next development iteration
Better exception message when tickDuration is too big

- Related: #1246
- Fix misc inspector warnings