new modules in trunk

[Paul Querna]

I've committed a few new modules to trunk tonight:

mod_ratelimit: Bandwidth Rate Limiting for Clients.
mod_heartbeat: Generates Multicast heartbeat messages containing the 
status of the server.

mod_heartmonitor: Collects these Multicast heartbeats for other modules 
to use.

mod_lbmethod_heartbeat: Module to Load Balance mod_proxy_balancer 
workers using the data from the heartbeats.

If people could take a closer look at mod_lbmethod_heartbeat especially, 
since it is completely new, and I don't really know the internals of 
mod_proxy that well, while the other ones are a little more battle tested.

Thanks,

Paul