Windows: Change show in folder code

[Demez]

Currently qimgv launches a new explorer process with "/select file", while this does work, it ends up opening a new window every time, even if a window with the file in the folder is open. This win32 code below (taken from a project of mine) allows you to select a file in a folder, and not open a new window if needed, it selects the file if the folder is already open in a window.

I might pull request it if I can get this project to compile on my own.

(btw i love using this image viewer it's so good)

const char* path_to_file = "C:\\path\\to\\cool.jpeg";
ITEMIDLIST* pidl         = ILCreateFromPath( path_to_file );

if ( pidl )
{
	SHOpenFolderAndSelectItems( pidl, 0, 0, 0 );
	ILFree( pidl );
}