Show more button v2

Before:
![screen shot 2014-10-13 at 17 23 48](https://cloud.githubusercontent.com/assets/2579465/4630512/d7764526-53ad-11e4-9656-c3b00970a49d.png)

After:
![screen shot 2014-10-13 at 17 23 35](https://cloud.githubusercontent.com/assets/2579465/4630518/dcf161b6-53ad-11e4-8cc3-08d4f6f88f5e.png)

Show more button is now moved to the pasteup-buttons.

What's next: I will move all of these `show more` buttons to pasteup-buttons and pasteup-palette.

as mentioned, can split this out into an external file - see https://github.com/guardian/frontend/pull/6469