Fix Issue 9

To make the code editor less dependent on screen resolution, my changes to the code editor being pull-requested against perform calculations using screen.availWidth and screen.availHeight to create the window in proportion to said bounds. Hopefully they will be accepted upstream... Screenshot of what the changes do attached below.
![screenshot 2013-07-17 at 11 18 51](https://f.cloud.github.com/assets/3030773/814002/702928a8-ef0d-11e2-8fc7-af5c91cc684b.png)