Added JSHint

This was mostly trivial:
* applied all flags, except for line length, which I though was overkill. Nevertheless, new code / commits should respect that.
* there was an error in tumblr.js, where a post of type 'conversation' would bring down the whole building
* also removed example sites which no longer have jquery lifestream

~~[laxbreak](http://www.jshint.com/docs/#laxbreak) is in there because nobody put them properly and most people would JSL compressed, where it doesn't matter anymore. I'll add another commit if you'd like to have it in.~~ Extra commit for linebreaks.