Improved flexibilty when specifying signGroups

Group membership is now determined with a function.  See config.js for
some examples.  If we want to include more information about markers in
markers.js, this model should be useful.

config.js

@@ -10,14 +10,23 @@
   };
 
 
-// define a list of pattern-label pairs.  Each label will appear
-// in the 'Signposts' control, allowing your users to quickly enable
-// or disable certain labels.  See below for some examples:
-var signGroups = {
-//    "Directions": /^#Direction/i,
-//    "Big Dig": /big\s*dig/i,
-//    "Warnings": /warning/i,
-};
+/* signGroups -- A list of signpost groups.  A signpost can fall into zero, one, or more than one
+ * group.  See below for some examples.
+ *
+ * Required: 
+ *     label : string.  Displayed in the drop down menu control.
+ *     match : function.  Applied to each marker (from markers.js).  It is returns true if the marker
+ *                        Should be part of the group.
+ *
+ * Optional:
+ *     checked : boolean.  Set to true to have the group visible by default
+ */
+var signGroups = [
+//    {label: "'To'", checked: false, match: function(s) {return s.msg.match(/to/)}},
+//    {label: "Storage", match: function(s) {return s.msg.match(/storage/i) || s.msg.match(/dirt/i) || s.msg.match(/sand/)}},
+//    {label: "Below Sealevel", match: function(s) { return s.y<64;}},   
+    {label: "All", match: function(s) {return true}}
+];
 
 // Please leave the following variables here:
 var markerCollection = {}; // holds groups of markers