buildfarm improvements

I have implemented several requested improvements, which I hope will 
prove useful. Since this whole piece of work exists for the benefit of 
the pg developers, I'm posting some info here.

The latest version includes these features:

. the log page shows the system type near the top "OS/Compiler/Architecture"
. the log page shows the script configuration data (other than the 
password) and including the script version number
. the changed files list(s) on the log page include CVS revision numbers.

An example showing all these can be seen at 
http://www.pgbuildfarm.org/cgi-bin/show_log.pl?nm=dog&dt=2004-12-17%2021:06:01

Constructive comments welcome as always.


cheers

andrew