Change Pager's unicode signs

The unicode signs don't get converted so I think it's safer to use "Next" and "Previous".

Chrome: 
![Screen Shot 2013-03-09 at 23 36 26](https://f.cloud.github.com/assets/648684/240403/3605ec3a-8912-11e2-856a-fdadcbc42694.png)

Safari:
![Screen Shot 2013-03-09 at 23 37 12](https://f.cloud.github.com/assets/648684/240404/4bd666d4-8912-11e2-962d-d6666a774560.png)