Blur effects by pseudo-elements and border-radius

- Use pseudo elements instead of `div.peg` to take blur effect, ie8+ support
- Fade blur effect by `border-radius` instead of `transform:rotate`, `border-radius` has better compatibility


Before:
![2013-10-18 1 07 44](https://f.cloud.github.com/assets/1676871/1358198/03a2fa78-37b6-11e3-92f8-3ce97c215927.png)

After:
![2013-10-18 1 08 35](https://f.cloud.github.com/assets/1676871/1358200/07db0572-37b6-11e3-8f89-1abc0802baae.png)