Regression testing system.

See test.mk for instructions.

Requirements:

GNU make            GNU extensions are used
inotify-tools       The Linux userland inotify tools
socat  >= 1.7.1.2   Netcat on steroids
                 See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=531078
                 for socat bug fixed in 1.7.1.2.
PostgreSQL >= 9.2.2? Right now there's patch 
                    https://commitfest.postgresql.org/action/patch_view?id=1001
                    if this makes it into pg then fine.  Meanwhile I've
                    applied this patch to a 9.2.1 psql that's in this
                    directory.  If the patch is rejected then I'll have to
                    use socat to interleave the error stream with the
                    query output.  (That would be messy, but doable.)
                    Note that the patched psql binary is not in darcs.
python >= 3.2       Needs argparse.  Should backport to 2.7.