Nifty thread naming updates

- allow setting a name prefix for the threads by calling setName() on the NettyClientConfigBuilder
- make netty actually name the threads in the boss and worker pool
  correctly by passing a ThreadNameDeterminer in.

Setting the name of the timer thread will only work after
- https://github.com/netty/netty/pull/1176 was applied
- the next version of netty gets released with this pull request applied
- the line
  `this.hashedWheelTimer = new HashedWheelTimer(renamingDaemonThreadFactory(prefix + "-timer-%s"));`
  is replaced by
  `this.hashedWheelTimer = new HashedWheelTimer(renamingDaemonThreadFactory(prefix + "-timer-%s"), ThreadNameDeterminer.CURRENT);`