VirtualBox Ubuntu 12.04 (Guest) Fixes

If you want to try the latest Ubuntu 12.04 Precise Pangolin alpha or a daily build in VirtualBox (guest), you'll stumble upon a few issues like: VirtualBox can't boot from the 32bit ISO because PAE is not enabled by default so you'll get a kernel error, the mouse isn't working or the screen is glitchy and black in Unity 3D after installing the VirtualBox Guest Additions from the repositories (required if you want to use Unity 3D).

So here is how to fix these issues and run the latest Ubuntu 12.04 Precise Pangolin build with Unity 3D in VirtualBox.