Issue #8: Improve Deployment Documentation

Update documentation for sign mode.

src/site/markdown/features/sign-mode.md

@@ -5,4 +5,22 @@ quick and cheap information displays.
 
 <a href="http://www.flickr.com/photos/atomictaco/6202909370/sizes/m/in/pool-624040@N24/"><img src="Sign.jpeg" /></a>
 
-Photo by Atomic Taco.
+Photo by Atomic Taco.
+
+To use sign-mode, use the [standard web interface](web.html) to browse to your favorite stop.  The URL for the page
+should have form like:
+
+http://your.host-name.com/where/standard/stop.action?id=X_Y
+
+To enable sign mode, simply replace the `standard` part of the URL with `sign`:
+
+http://your.host-name.com/where/sign/stop.action?id=X_Y
+
+There are a number of parameters you can add to the URL to tweak the behavior of the sign:
+
+* `title=...` - By default, the sign uses the current stop name as a title.  This option allows you to override the title.
+* `showTitle=false` - Alternatively, you can hide the title completely.
+* `route=X_Y` - Specify a route id to indicate that only this route should be show.  Can be repeated.
+* `minutesBefore=N` - Excludes vehicles that departed more than N minutes ago. 
+* `minutesAfter=N` - Exclude vehicles arriving more than N minutes from now.
+* `refresh=N` - Automatically refresh the page every N seconds.