Provide option of showing panels as well

[hirad]

First of all, this is a wonderful plugin! Thanks so much for making it!

One improvement I would love would be the ability to show as well as hide panels. Currently, under the "When opening an interface file" options, there is a "Show utilities area" but there is no corresponding "show navigator area" for "When opening a text document".

If we could have dropdowns beside each checkbox with "Show" or "Hide" options (like Xcode's own behaviour preferences screen), that would make it much more flexible!

Thanks!