Please add a center() method that mirrors the functionality of the jquery version.  It is useful to either recenter a window that has been moved, or if a value is set on the windowStyle property, it would still be useful to center and fill in any missing values.

For example, I might want to specify the top of the window, but would still like it centered on the screen horizontally, or specify the left or right position of the window and have it centered vertically.

Thanks.