Make Switchboard window a fixed-width and un-resizeable.

[Sam Hewitt]

The content of Switchboard's window is sufficiently low that we needn't allow it to maximize or get any larger than a set default size.

1. Prevent manually resizing of the window (including maximizing).
2. Set a fixed-width for the window –I think 820 pixels is a good width as it's sufficient for 5 items/row on the home pane.
3. Let plugs resize the window vertically as needed –it adjusts up/down to the size of the content including that of the home pane.

Doing this prevents too much whitespace between elements if a window is made too large and we'll be able to make the experiences between plugs consistent (including 3rd party plugs).

[quassy (quassy)]

Please, please don't do this. It is bad UI design and it should not be that hard to implement a halfway adaptive design.