add JoinIterator, an Iterator adapter that creates a String out of an Iterator whith elements that implement ToString
add comments
JoinIterator => StringJoiner
fix travis error and String::from_str() stupidity
ultra-trivial style fix ;)
created iter module
second shot at style fix
made StringJoiner pub and added docs
oops, more docs
Merge pull request #7 from flo-l/master

Add an Iterator.join() method