Keep track of window position and size after closing

[cjfcode]

[cjfcode]

Added this method for remembering the position and size of the window.

I tested it on Windows 10 x64 with a single monitor configuration and it seems to work great, but some users in the comment section claim this method doesn't work properly when maximizing the window on a second monitor, closing the program, and opening it again. Needs testing on a multiple monitor configuration.

If it does work, I need to refactor the code to make use of the functions already in place in the NativeMethods class. If it doesn't work, try this nuget package.

If neither of those methods work, manual tweaking may be necessary.