Add socialToolbar component

Doesn't allow any configuration, i feel like we open stuff up too much to config and there's no need yet.

Uses some funky line breaking indenting in places, not normal.

Has a looping spec which may or may not help matters. Removes duplication but makes debugging more awkward. I'm indifferent.

Feel free to push back on any of the above if needs be. Definitely feel free to improve my regex where possible. I feel like maybe i should be making use of the $1 stuff to reduce duplication of the separator but not sure if that's true or if you can in that case.

Feeling antisocial after all this.
No huge performance benefit, but `this.shares[i]` is used a few times here and I feel it would be nicer to read if we had just `var share = this.shares[i];`.