Added

• Add command line flag for using e10s enabeld Firefox by @martionsideofthemoon
• Allow providing custom profiels

Changed

• Allow binding to an IPv6 address by @juangj
• By default, connect to host-agnostic localhost by @juangj
• Make GeckoContextParameters public
• Update dependencies

Fixed

• Squash rustc 1.6 warnings by using std::thread::sleep(dur: Duration)