Hello there modmyi users!
There was a thread here that explained how to configure each app, what to do when the close button is pushed. To really exit the app, or to go in multitasking. A file had to be modified in each app.
I used the search but can't find it anymore.
Anyone?!
I have no idea what that thread was about, but the solution I use is MultiCleaner. Click on the home button and the app is backgrounded, click and hold shortly - and it's killed. You can also create a separate rule for every single app.