Use the latest rendering mode for IE.

Related to #74.

This fix will make IE10+Win8 recognize that elegant page is written in HTML5, and could fix lots of rendering issues.

Before this fix:
![image](https://f.cloud.github.com/assets/3761553/1652025/970996e4-5afe-11e3-9b41-fdecd819ec93.png)

After:
![image](https://f.cloud.github.com/assets/3761553/1652028/b5a0537c-5afe-11e3-98d3-1ec80cfcd137.png)