Iconsets don't work for plugin icons

[douglas]

The new iconset functionality doesn't work for assinging icons to a plugin.

[douglas]

r1115 Updates the Tango iconset to include an icon for the SmartReplace? plugin. This doesn't take effect because the iconset is parsed, but not kept with the editor to replace incoming icon registrations...

[ray]

It works if you explicitly select "Tango" as _editor_icons. The iconset XML is parsed and applied after the plugins have registered their buttons.

But I think we should leave the default icons in the images folder and the respective definitions in the code. That way we save one loading and parsing pass.

Also people tend to like to throw away everything they see fit, so we have the iconsets folder as optional, like the plugins folder is optional and modules isn't.

Along the way: Could I - as the author of the plugin - ask for not replacing the SmartReplace? icon? Is there anything special you don't like about it? (Have you seen that I just recently crafted a new one to better fit with the Tango style?)