Some more unicode tests

Since this blog post [1] caused some stir, I added
tests corresponding to how most languages referred
to are broken. Naturally, that's not the case for
Elixir.

[1] http://mortoray.com/2013/11/27/the-string-type-is-broken/
Fix comment
Merge pull request #1900 from krestenkrab/krab-unicode

In response to "The string type is broken"