[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.
Not sure whether we need to configure areas using system properties for `PooledByteBufAllocator`
```
-Dio.netty.allocator.numDirectArenas=... -Dio.netty.allocator.numHeapArenas=...
```
Reference: http://mail-archives.apache.org/mod_mbox/flink-commits/201406.mbox/%3Cd2256046eecf4238a98ddf0625a31e93@git.apache.org%3E