Merge pull request #215 from linghutiantian/dev/dgram_socket

mtr-packet: use ICMP and UDP without privilege on linux

diff --cc configure.ac
Simple merge

diff --cc packet/command.c
Simple merge

diff --cc packet/construct_unix.c
Simple merge

diff --cc packet/deconstruct_unix.c
Simple merge

diff --cc packet/deconstruct_unix.h
Simple merge

diff --cc packet/probe.c
Simple merge

diff --cc packet/probe.h
Simple merge

diff --cc packet/probe_cygwin.c
Simple merge

diff --cc packet/probe_cygwin.h
Simple merge

diff --cc packet/probe_unix.c
Simple merge

diff --cc packet/probe_unix.h
Simple merge

diff --cc packet/wait_unix.c
Simple merge