Enabled by setting the --debug-addr command-line option.

This provides some discovery capabilities to radiod and redirectord, so
that in most cases fewer command-line options are required for operation.

Split networking is where nodes communicate among themselves on a
private network (for example when behind a NAT infrastructure). This
change adds the --internal-ip option to radiod, that advertises a
separate IP for internal communication.

Also removed some unnecessary duplication of code from net/http.

Refactor the HTTP handler hierarchy to make it simpler.

Replace the ghost logging handler with a simpler one, that fires as soon
as the HTTP request headers are sent (this is a better solution for
long-lived connections).

Add a debug page to track long-lived HTTP request.

Add tests for the HTTP server.

Adds optional transcoding parameters to a Mount. Each node will then
start a master election for every transcoded stream, and the master will
run liquidsoap to re-encode the data. Transcoding mounts are identical
in other respects to normal mounts, except that liquidsoap acts as a
source for them.

Refactor the load balancing code using a generic traffic control
abstraction that gives the user more control over the final logic (for
the moment this is configured via a command-line parameter).

Introduce node names, allowing a node to have multiple IP addresses.
Also, make the front-end code IPv6-aware and support AAAA records.