buildfarm enhancements

I have made a new release of buildfarm client code, which has some small
bug fixes and enhancements, and also has the substantial changes
necessary to allow the client to run on Windows. That client can be
obtained from http://pgfoundry.org/frs/?group_id=1000040

I have also made some modest changes to the web site - the main status
"dashboard" page no longer shows results older than 30 days - that way
if a client goes silent for some reason we aren't clogged forever. By
contrast, the history page for each member/branch now lists up to the
last 240 builds, rather than just the last 30 - so we can go quite a
long way back if necessary.

cheers

andrew