Custom Fonts, CSS stylesheet service, String version service

The patch enables custom fonts for your Echo application. For instructions on how to include a custom font see InteractiveApp.java and InteractiveServlet.java.

The pull requests includes also a general CSS stylesheet service and a string version service (as contributed by XSoftBG)

![image](https://f.cloud.github.com/assets/3050757/470011/a48f20f0-b6e8-11e2-99ea-be78a2fa341a.png)