Remove shadow from solarized theme.

This improves the solarized themes, so that they look simliar to other editors.
![screen shot 2014-03-17 at 16 43 59](https://f.cloud.github.com/assets/790842/2437893/b790ddb0-adeb-11e3-94b1-b5a375011ef3.png)
![screen shot 2014-03-17 at 16 44 16](https://f.cloud.github.com/assets/790842/2437894/b7a65eba-adeb-11e3-8f9a-a12fa810942e.png)