[DONE-4] Wiki - Make thumbnails from SVG

SVGs cannot be converted to thumnails:
http://wiki.opensourceecology.de/wiki/Datei:OSEG_Logo_Design_1.svg
Reason: rsvg: command not found

The rsvg command depends on this package: libmagickcore3-extra.
Aron, can you install this package or tell me how I can install it?

DONE. Es fehlten die Pakete: librsvg2-bin, librsvg2-common