Update version 0.5.2.1

a) fixes "major vulnerability in the HTML filter" in the web interface

http://www.freenetproject.org/ says:
> 18th July, 2003 - Upgrade to 0.5.2.1
> Freenet 0.5.2.1 fixes amongst other things a
> major vulnerability in the HTML filter. Anyone running
> Freenet should upgrade.

b) situation seems to be serious and urgent update is required.

PR: 54652, 54580 and 54430
Submitted by: Stefan Walter <sw@gegenunendlich.de>
Suggestion by: kuriyama