Update to bootstrap 3 and add search capability


I have partially rewritten templates to use bootstrap 3 ​​and I added a text field on the top bar to filter rows according alias and translation value.

It would be appropriate to update the image of the README and TODO

![symfony2 translations editor 2013-12-19 13-53-15](https://f.cloud.github.com/assets/1287902/1782409/92f307e6-68ac-11e3-8c82-78741bc9b28f.png)