https://forums.fedoraforum.org/showthread.php?26875-How-To-Mime-Types-and-file-associations-with-FC3-Gnome-2-8

to do new associations, want ~/.local/share/
    .../applications/xxx.desktop = desktop launcher file; use %f in the Exec= to substitute file name
    .../applications/defaults.list = shows the default application only
                mime/type=default_player.desktop
    .../applications/mimeinfo.cache
                mime/type=first_player.desktop;second_player.desktop

Per <https://help.gnome.org/admin/system-admin-guide/stable/mime-types-custom-user.html.en>, 
you might even be able to add new types

might use `update-mime-database ~/.local/share/mime` and `update-desktop-database`

yeah, I think I need to add those mime-types... looking at other files (/usr/share/mime/packages/*), it seems
I can put them all in one file, then use the `update` commands

    update-mime-database ~/.local/share/mime
    update-desktop-database -v ~/.local/share/applications

For the .desktop files, I found this reference:
    https://developer.gnome.org/desktop-entry-spec/
So that explains how to do Icons and other things...
    find ~/.gnome2 -iname "*.desktop" -exec egrep -iH "icon" {} \;
        => shows some of the icons I've used 


icon-computer-ccenter.png
icon-computer-restart.png
icon-character-map.png