Well, really re-use the existing documentation, but make doxygen do
something with it. I'm not fully satisfied with the result, but it will do
for now, and getting more information on what the messages really mean will
help.
Here's a patch to NET_SendToAll() which was always
broken: it never skipped non-connected clients.
Depending on the compiler, it would wait the whole
5 seconds of its blocktime before it gave up.
While there, changed its blocktime argument to
double (the comparison is against a double.)
