Fix permalink with more than 1 digit in id

Permalink feature was working for #9 but failing for #12.

wifiwithme/static/map.js

@@ -117,7 +117,7 @@ $( document ).ready(function() {
 
         // Open popup if hash is present.
         if (window.location.hash) {
-            var id = window.location.hash.substr(-1);
+            var id = window.location.hash.slice(1);
             openMarker(id);
         }
         else {
@@ -130,7 +130,7 @@ $( document ).ready(function() {
 
         // Bind window hash change
         window.onhashchange = function() {
-            var id = window.location.hash.substr(-1);
+            var id = window.location.hash.slice(1);
             openMarker(id);
         }