[TACHYON-62] Netty

Netty implementation of the data server.

This patch is not done yet.  Its intent is to show the work I have right now for commenting.

This PR should not be merged until performance results come in.
Which of two has a better performance? If certain, should document here. e.g. NIO or EPOLL is recommended.

It will be also good to document the difference between two options.