--- a/js/flot/jquery.flot.stack.js
+++ b/js/flot/jquery.flot.stack.js
@@ -1,1 +1,185 @@
+/*
+Flot plugin for stacking data sets, i.e. putting them on top of each
+other, for accumulative graphs.
 
+The plugin assumes the data is sorted on x (or y if stacking
+horizontally). For line charts, it is assumed that if a line has an
+undefined gap (from a null point), then the line above it should have
+the same gap - insert zeros instead of "null" if you want another
+behaviour. This also holds for the start and end of the chart. Note
+that stacking a mix of positive and negative values in most instances
+doesn't make sense (so it looks weird).
+
+Two or more series are stacked when their "stack" attribute is set to
+the same key (which can be any number or string or just "true"). To
+specify the default stack, you can set
+
+  series: {
+    stack: null or true or key (number/string)
+  }
+
+or specify it for a specific series
+
+  $.plot($("#placeholder"), [{ data: [ ... ], stack: true }])
+  
+The stacking order is determined by the order of the data series in
+the array (later series end up on top of the previous).
+
+Internally, the plugin modifies the datapoints in each series, adding
+an offset to the y value. For line series, extra data points are
+inserted through interpolation. If there's a second y value, it's also
+adjusted (e.g for bar charts or filled areas).
+*/
+
+(function ($) {
+    var options = {
+        series: { stack: null } // or number/string
+    };
+    
+    function init(plot) {
+        function findMatchingSeries(s, allseries) {
+            var res = null
+            for (var i = 0; i < allseries.length; ++i) {
+                if (s == allseries[i])
+                    break;
+                
+                if (allseries[i].stack == s.stack)
+                    res = allseries[i];
+            }
+            
+            return res;
+        }
+        
+        function stackData(plot, s, datapoints) {
+            if (s.stack == null)
+                return;
+
+            var other = findMatchingSeries(s, plot.getData());
+            if (!other)
+                return;
+
+            var ps = datapoints.pointsize,
+                points = datapoints.points,
+                otherps = other.datapoints.pointsize,
+                otherpoints = other.datapoints.points,
+                newpoints = [],
+                px, py, intery, qx, qy, bottom,
+                withlines = s.lines.show,
+                horizontal = s.bars.horizontal,
+                withbottom = ps > 2 && (horizontal ? datapoints.format[2].x : datapoints.format[2].y),
+                withsteps = withlines && s.lines.steps,
+                fromgap = true,
+                keyOffset = horizontal ? 1 : 0,
+                accumulateOffset = horizontal ? 0 : 1,
+                i = 0, j = 0, l;
+
+            while (true) {
+                if (i >= points.length)
+                    break;
+
+                l = newpoints.length;
+
+                if (points[i] == null) {
+                    // copy gaps
+                    for (m = 0; m < ps; ++m)
+                        newpoints.push(points[i + m]);
+                    i += ps;
+                }
+                else if (j >= otherpoints.length) {
+                    // for lines, we can't use the rest of the points
+                    if (!withlines) {
+                        for (m = 0; m < ps; ++m)
+                            newpoints.push(points[i + m]);
+                    }
+                    i += ps;
+                }
+                else if (otherpoints[j] == null) {
+                    // oops, got a gap
+                    for (m = 0; m < ps; ++m)
+                        newpoints.push(null);
+                    fromgap = true;
+                    j += otherps;
+                }
+                else {
+                    // cases where we actually got two points
+                    px = points[i + keyOffset];
+                    py = points[i + accumulateOffset];
+                    qx = otherpoints[j + keyOffset];
+                    qy = otherpoints[j + accumulateOffset];
+                    bottom = 0;
+
+                    if (px == qx) {
+                        for (m = 0; m < ps; ++m)
+                            newpoints.push(points[i + m]);
+
+                        newpoints[l + accumulateOffset] += qy;
+                        bottom = qy;
+                        
+                        i += ps;
+                        j += otherps;
+                    }
+                    else if (px > qx) {
+                        // we got past point below, might need to
+                        // insert interpolated extra point
+                        if (withlines && i > 0 && points[i - ps] != null) {
+                            intery = py + (points[i - ps + accumulateOffset] - py) * (qx - px) / (points[i - ps + keyOffset] - px);
+                            newpoints.push(qx);
+                            newpoints.push(intery + qy);
+                            for (m = 2; m < ps; ++m)
+                                newpoints.push(points[i + m]);
+                            bottom = qy; 
+                        }
+
+                        j += otherps;
+                    }
+                    else { // px < qx
+                        if (fromgap && withlines) {
+                            // if we come from a gap, we just skip this point
+                            i += ps;
+                            continue;
+                        }
+                            
+                        for (m = 0; m < ps; ++m)
+                            newpoints.push(points[i + m]);
+                        
+                        // we might be able to interpolate a point below,
+                        // this can give us a better y
+                        if (withlines && j > 0 && otherpoints[j - otherps] != null)
+                            bottom = qy + (otherpoints[j - otherps + accumulateOffset] - qy) * (px - qx) / (otherpoints[j - otherps + keyOffset] - qx);
+
+                        newpoints[l + accumulateOffset] += bottom;
+                        
+                        i += ps;
+                    }
+
+                    fromgap = false;
+                    
+                    if (l != newpoints.length && withbottom)
+                        newpoints[l + 2] += bottom;
+                }
+
+                // maintain the line steps invariant
+                if (withsteps && l != newpoints.length && l > 0
+                    && newpoints[l] != null
+                    && newpoints[l] != newpoints[l - ps]
+                    && newpoints[l + 1] != newpoints[l - ps + 1]) {
+                    for (m = 0; m < ps; ++m)
+                        newpoints[l + ps + m] = newpoints[l + m];
+                    newpoints[l + 1] = newpoints[l - ps + 1];
+                }
+            }
+
+            datapoints.points = newpoints;
+        }
+        
+        plot.hooks.processDatapoints.push(stackData);
+    }
+    
+    $.plot.plugins.push({
+        init: init,
+        options: options,
+        name: 'stack',
+        version: '1.2'
+    });
+})(jQuery);
+