Add a selectable list.
Add j/k navigation.
Switch between two different lists.
Parse VBoxManage to get a list of VMs.
List certain VM properties on the second screen.
Add different properties.
Break header and footer into separate variables.
Add pop ups for editing individual values.
Populate changed values into the main window.
Modularize the whole screen switching more.

It was getting a real pain to move keep track of everything in their own
variables. This way, it should be easier to add more screens and such.
Add some more intuitive key-bindings.
Start off with a NIL screen.
Add concept of a screen stack.

This should make it easier in the future to add more screens and navigate
between them.
Add arguments to screens for easier passing of info.
Remove some dead code.
Add a screen that lists all USB devices.
Use UUIDs to determine which host a device is attached to.
Utilize all attributes for the USB list.
Toggle USB devices with Space.
Change README to reStructuredText.