flowgrind: fix lintian warning in manpage

Fixes the following lintian warning:
W: flowgrind: manpage-has-errors-from-man usr/share/man/man1/flowgrind.1.gz 92: a newline character is not allowed in an escape name
Travis OS X support
Merge branch 'master' of github.com:flowgrind/flowgrind into up-master
Ignore OS X builds for now since flowgrind is not ready for OS X
flowgrind: fix IPv4 test connection with IPv6 control connection