Initial support for persisting selections

.gitmodules

 [submodule "externals/flot"]
 	path = externals/flot
 	url = https://github.com/FooBarWidget/flot.git
+[submodule "externals/jquery.history"]
+	path = externals/jquery.history
+	url = https://github.com/tkyk/jquery-history-plugin.git

externals/jquery.history

+Subproject commit 09cdb9b6a13924152b67d89da57bb912f04fb0fc

index.html

   <script src="externals/flot/jquery.flot.js" type="text/javascript"></script>
   <script src="externals/flot/jquery.flot.pie.js" type="text/javascript"></script>
   <script src="externals/flot/jquery.flot.selection.js" type="text/javascript"></script>
+  <script src="externals/jquery.history/jquery.history.js" type="text/javascript"></script>
   <script src="data.php" type="text/javascript"></script>
   <script type="text/javascript">
    var previousPoint = null;
      var startDate = parseInt(ranges.xaxis.from.toFixed());
      var endDate = parseInt(ranges.xaxis.to.toFixed());
     
-     showSelectedMonths(startDate, endDate, 0); 
+     $.history.load('start:' + startDate + ';end:' + endDate + ';type:expenses'); 
     });
 
     $('#history').bind('plotclick', function(event, pos, item) {
      if (item) {
-      showSelectedMonths(item.datapoint[0], item.datapoint[0], item.seriesIndex == 0, item.seriesIndex == 1);
+      $.history.load('start:' + item.datapoint[0] + ';end:' + item.datapoint[0] + ';type:' + (item.seriesIndex == 0 ? 'income' : 'expenses'));
      }
     });
 
      $('#historytable .data').hide();
      $('#historytable .category' + item.series.label.replace(/[^a-zA-Z]*/g, '')).show();
     });
+
+    $.history.init(function(hash) {
+     var match = /start:([0-9]+);end:([0-9]+);type:(income|expenses)/.exec(hash);
+
+     if (match != null) {
+      showSelectedMonths(parseInt(match[1]), parseInt(match[2]), match[3] == 'income', match[3] == 'expenses');
+      plots.history.setSelection({ xaxis: { from: parseInt(match[1]), to: parseInt(match[2]) }});
+     }
+    });
    });
   </script>
   <style type="text/css">