[TACHYON-62] Implement a Netty based DataServer
upgraded netty.  moved worker shutdown after boss.  style
got transferTo to pass tests
refactor pipeline and added commented out code for next test
enable switch between epoll and nio
testing out epol with file region
moved file region logic to response encoder
moved nio server to nio package.  made a new DataServer interface to abstract over the implementations
pluggable network type
added sync group
more opts for netty
added mapped file support
more data server tests and test refactor
removed mapped file transfer type
updated netty
made netty settings configurations
removed sync group since it slowed things down
runtime
added file transfer as a config
Merge pull request #333 from dcapwell/netty

[TACHYON-62] Netty