Update icons, use more universal names
Gigolo icons look a little broken as many icon themes no longer provide some of the older gtk-
named icons.
I'm a little unsure on the decision for using Play/Stop as the connect/disconnect buttons. But network-related icons are very inconsistent among icons themes in both name and look, and Play/Stop seemed to be the most legible. Another option I thought might be Run/Cancel. Symbolic network icons are much more common and I think would work, but it looked strange to use 2 symbolic icons and then the rest of the toolbar icons be non-symbolic. Maybe changing the toolbar icons to all symbolic would be better?
Also changing Bookmark Manager -> Edit button to edit-select-all is just okay but seemed to be provided by every icon theme I tried. Some other options were document-properties, document-page-setup.
Oh, and also this does not update the dialog buttons (Cancel, Ok, Connect..). That looks like it might require a little code refactoring.
This drops a lot of the legacy gtk- prefixed icons in favor of freedesktop naming. In some cases, trying to pick icon names that are available in more themes.
Changed look
- Connect and Disconnect changed to Play and Stop Network-related icon names are not well standardized and many themes are missing gtk-connect, network-connect, etc or only offer them as symbolic icons.
- Bookmark Manager changed from gtk-edit to user-bookmarks
- Bookmark Manager -> Edit changed from gtk-edit to edit-select-all
- Used symbolic close icon for closing side panels
The rest of the names should not change the appearance of the icons