add messaging.c
add libgc
announce guile version
announce PQlib version
implement simple message polling

Poll zmq sockets at each zmq_poll event or timeout.
place zmq sockets under /var/lib/gusher/signals

Name zmq endpoints with symbols and map symbols to zmq socket space
as "ipc:///var/lib/gusher/signals/<symbol>.zmq"
merge zmq sockets into main polling loop

rather than polling individually outside zmq_poll()