Shadowsocks plugin tcp_and_udp mode

[xabbok255]

Ability of Shadowsocks plugin to work with udp ("mode": "tcp_and_udp").

resolves #3888

[xabbok255]

I hope I added everything correctly

[xabbok255]

Yep, please also update the Makefile for new version

I've updated the version in Makefile @mimugmail

[Monviech]

@mimugmail Can we merged this? Somebody on reddit wanted it too already: https://www.reddit.com/r/opnsense/comments/1cprc42/shadowsocks_how_to_make_changes_permanent/

[mimugmail]

Sure, I already approved, maybe @fichtner can merge?

[fichtner]

Sure, I already approved

Not as far as I can see (approval check mark missing) but I take it that's a yes :)

[fichtner]

Merged, thanks!