Add an explanation of the columns in the main display.

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@1063 d4fa192b-c00b-0410-8231-f00ffab90ce4

bin/varnishstat/varnishstat.1

@@ -26,6 +26,18 @@ statistics once and exit.
 .It Fl V
 Display the version number and exit.
 .El
+.Pp
+The columns in the main display are, from left to right:
+.Bl -enum
+.It
+Total since startup
+.It
+Delta since last update (normally the last second)
+.It
+Average over process lifetime
+.It
+Descriptive text
+.El
 .Sh SEE ALSO
 .Xr varnishd 1 ,
 .Xr varnishhist 1 ,