* Added a status page that shows all the currently executing build steps.

* Store the system type in the BuildSteps table.
* Don't query the queue size when serving static pages.  This prevents
  two unnecessary database queries per request.

src/script/hydra_build.pl

@@ -264,6 +264,7 @@ sub doBuild {
                         , type => 0 # = build
                         , drvpath => $drvPathStep
                         , outpath => $2
+                        , system => $3
                         , logfile => $4
                         , busy => 1
                         , starttime => time