map: save bounds on drag end store on resetview

lib/map.js

@@ -122,6 +122,7 @@ define(["map/clientlayer", "map/labelslayer",
       var self = this
       var barycenter
       var groupOnline, groupOffline, groupNew, groupLost, groupLines
+      var savedBounds
 
       var map, userLocation
       var layerControl
@@ -134,6 +135,10 @@ define(["map/clientlayer", "map/labelslayer",
           disableTracking()
       })
 
+      function saveView() {
+        savedBounds = map.getBounds()
+      }
+
       function enableTracking() {
         map.locate({watch: true,
                     enableHighAccuracy: true,
@@ -199,6 +204,7 @@ define(["map/clientlayer", "map/labelslayer",
 
       map.on("locationfound", locationFound)
       map.on("locationerror", locationError)
+      map.on("dragend", saveView)
 
       map.addControl(locateUserButton)
 
@@ -280,6 +286,8 @@ define(["map/clientlayer", "map/labelslayer",
         if (!nopanzoom)
           if (m)
             goto(m)
+          else if (savedBounds)
+            map.fitBounds(savedBounds)
           else
             resetZoom()
       }