Localize strings in copypaste SOCKS sample

ran grunt test

There is a drop down that switches the language between Italian and English.
After migrating the popup to Polymer I can try a RTL language.
Glad to see that merging of `third_party` from multiple repos seems to be working!

I don't think there's any need to have `third_party/lib/i18n` -- let's just push it up to `third_party/i18n`.