When we just received a message in a groupchat room and we close it Gajim asks if we really want to close it.

When we just received a message from a contact and we close it's chat window/tab Gajim asks if we really want to close it.

(code in preferences window is still needed)

first tab in preferences is working with instant apply the only thing that does not work correctly is iconstyle_combobox i will fix it in about an hour from now

less deep indentation