Merge pull request #3 from alexander-zimmermann/master

Docs: fix generic, Debian, Ubuntu, and FreeBSD installation instruction
bug fix for DSCP marking

https://bugs.launchpad.net/flowgrind/+bug/1196940

Patch by Midori Kati, sent in by Lars Eggert.
nits: unify parameter naming in fg_socket.h
flowgrind: fix off by one error in RPC port parsing

This is a fix for "can't specify port number of RPC server"
https://bugs.launchpad.net/flowgrind/+bug/1196972

Reported by Lars Eggert.
Update NEWS file
prepare flowgrind-0.6.1