Inkscape version 0.91 has a new Symbols dialog, with which you can manage symbols. The symbols can come from libraries that are already installed, or from a library that you install, or custom symbols that you create on the canvas.
Animated gif, click on Magnifier icon to see.
Vamox icons in fedora 20 live CD http://gnome-look.org/content/show.php?content=95244