fix shutdown of collector/sender pair
does the timeout mechanism work to prevent starvation?
add more logging messages
memory management like daemon, not application
turn memory cache into disc cache
discontinue "select" on SIGINT
discontinue "select" on "accept"
bind "read_tables" and "produce_output" in transaction for shell scripts
don't allocate each field in "relation" separately.
close socket correctly on shutdown of refinery, so that it can be re-used quickly
allow split strings in config files