Integration of social media

This post was heavily edited 3/11

This should go on page 2 of the bookmarklet form as mentioned in #116 and #118.

For twitter a simple tweet from the users own twitter account is fine. This can take the form of <a href="https://twitter.com/intent/tweet?related=OA_Button&text=I+hit+a+paywall!&url=http%3A%2F%2Foabutton%2Fitems%2F123&via=OA_Button">pre-filled form as suggested by @hubgit below</a>. The code to do this can be found <a href="https://dev.twitter.com/docs/tweet-button">here</a> I think. If possible it would be good for this prefilled text to be taken from the users story - but don't sweat about this. If possible it would be good to have the post automatically tagged with #paywall 

For facebook a "share to timeline" button would be fine. Again if it could take it's default post from the users story that would be nice. If not no worries. If possible it would be good to have the post automatically tagged with #paywall

Can we also have a facebook Like button and a Follow button for twitter on page 2( #118) The Like button should be for the url: https://www.facebook.com/openaccessbutton and the follow button should be for oa_button (example here https://twitter.com/about/resources/buttons#follow)

Summarising. On page 2 it would be good if:

- [ ] There was a FB like button
- [ ] There was a twitter follow button
- [ ] There was the option to share a users story over a users twitter account
- [ ] There was the option to share a users story over facebook with a post to wall
This ticket merges #19 and #7.