Start a hidden rather than minimised vncconfig

This is plumbing that we shouldn't have to annoy the user with a
separate window for.
diff --git a/unix/vncserver b/unix/vncserver
index b962738..9ff2441 100755
--- a/unix/vncserver
+++ b/unix/vncserver
@@ -337,7 +337,7 @@
 }
 $ENV{VNCDESKTOP}= $desktopName;
 
-system($exedir."vncconfig -iconic >> " . &quotedString($desktopLog) . " 2>&1 &");
+system($exedir."vncconfig -nowin >> " . &quotedString($desktopLog) . " 2>&1 &");
 
 if ($opt{'-fg'}) {
     system("$vncUserDir/xstartup >> " . &quotedString($desktopLog) . " 2>&1");