libpanel-applet3

I’ve finally found some time to blog about this. The bonobo-less gnome-panel branch was merged into master, so since version 2.31.2 gnome-panel doesn’t depend on bonobo anymore. The API is mostly the same, but there are some minor changes since the old API exposed bonobo stuff. This of course means that applets need to be ported to the new API. There’s already a GNOME Goal with a porting guide, and I already ported most of the gnome-applets so there are a few examples too.