Add function getWindowAsImage to capture single Window

[p3rd1x]

Added the function getWindowAsImage() to screenshot a specific window. Takes the current window if hwnd == None or any other window specified by the window handle hwnd. With win32gui.EnumWindows one can obtain the window handles of all top-level windows.

[ivan]

Thanks, that does seem like something reasonable to include here, though you could also do it by having that helper function in your own program.

I won't have time to do another release of Desktopmagic any time soon, so if you need this functionality, I recommend either that or maintaining a fork.