Add Save Changes feature on file close attempts

[zshoals]

Closing a file that has not been saved already gives you a prompt to ignore map changes or to cancel the close attempt. It seems strange to me that direct Save functionality is not in this prompt as well.

[deepnight]

I actually had a Save button here, but it was slightly more confusing to have 3 buttons instead of 2. I will give that another try :)

[deepnight]

I went for a more straightforward prompt question. Works better imho: