[v57] - coming soon functions

[masterjp]

There are a few features and menus in XnView that currently still display “coming soon” messages.
Some of these are features that already exist in principle, but presumably need to be reimplemented in every window or section of the program. Perhaps this can be fixed.

For example, when mark images, you can’t open the menu at the top that displays the settings menu. Instead, the message “Coming soon” appears. This kind of menu already exists.