= String join
A helper trait for joining an iterator by a string-like thing using a python-like syntax
== Usage
----
use string_join::Join
"=>".join(["a", "b"].iter().cycle().take(5)); // => "a=>b=>a=>b=>a"
" ".join(&["a", "b", "c"]); // => "a b c"
let mut f = File::write("foo.txt").unwrap();
"\n".write_join(&mut f, &["a", "b", "c"]); // std::io::Result<5> (writes joined string to writer and returns a result
// with either the number of bytes written, or a std::io::Error
----