Changes:
1. This version is downloaded from
https://fast.dpdk.org/rel/dpdk-17.11.2.tar.xz.
2. Adapt the new interface `rte_ring_dequeue_burst`.
3. Change the type of `port_id` from uint8_t to uint16_t.
4. Just link libdpdk.a instead of the other libaries.
5. Install libnuma-dev first.
6. Update the documents.
logwang