p2psim: a simulator for peer-to-peer (p2p) protocols

Various bugfixes.
A new protocol, Accordion.
Churneventgenerator: different node life time distributions, in particular, heavy-tailed life-time (Pareto) distribution.
Euclidean topology now takes one argument: number of nodes. See the example.
libtask, and therefore p2psim, is now portable to Linux (x86 and AMD64), FreeBSD (4 and 5), Mac OS, SunOS, and NetBSD.
More detailed statistics tracking.
Removed dead code from Chord and added support for Accordion in the location table.