Pasteup-buttons update and show more button fix

1. The pasteup-button mixin is just small refactoring to remove some styles from mixin so they are not being repeated.

2. Removing some unnecessary elements and class from show more button on football matches page.

3. Trying to fix (make it less visible) the 'Guardian font baseline issue' on show more button

Chrome on Mac:
Now:
![screen shot 2014-12-12 at 14 59 11](https://cloud.githubusercontent.com/assets/2579465/5413516/752f0d0e-820f-11e4-9667-7b38577c03dc.png)

After:
![screen shot 2014-12-12 at 14 59 33](https://cloud.githubusercontent.com/assets/2579465/5413520/815ceb3c-820f-11e4-82a1-ed465f0f897f.png)

Firefox on Mac:
Now:
![screen shot 2014-12-12 at 15 00 01](https://cloud.githubusercontent.com/assets/2579465/5413526/9420acea-820f-11e4-8ac7-b729d3740800.png)

After:
![screen shot 2014-12-12 at 15 00 29](https://cloud.githubusercontent.com/assets/2579465/5413534/a56b4b2c-820f-11e4-8147-c2f8a2647bd0.png)

Chrome on Windows:
Now:
![screen shot 2014-12-12 at 15 02 09](https://cloud.githubusercontent.com/assets/2579465/5413553/de03b258-820f-11e4-986c-36b35c7bbb13.png)

After:
![screen shot 2014-12-12 at 15 02 26](https://cloud.githubusercontent.com/assets/2579465/5413559/ebc8bce4-820f-11e4-8856-1f3880b81819.png)

It also fixes the "Mobile breakpoint jump":
Going to mobile from desktop:
Now:
![screen shot 2014-12-12 at 15 04 37](https://cloud.githubusercontent.com/assets/2579465/5413600/35f50c96-8210-11e4-864a-2939a0f339f7.png)

After:
![screen shot 2014-12-12 at 15 05 01](https://cloud.githubusercontent.com/assets/2579465/5413619/47c02140-8210-11e4-9bbd-bde7440c6b28.png)