support lineMode=staircase for flot

[client9]

nice project!

It is likely I'm Doing This Wrong, so I'm not doing a full branch.

But this patch adds staircase mode to Flot.

--- a/jquery.tswidget.js
+++ b/jquery.tswidget.js
@@ -166,6 +166,12 @@ function find_definition (target_graphite, options) {
             if(resp_graphite.length == 0 ) {
                 console.warn("no data in graphite response");
             }
+
+            var lineMode = false;
+            if ('lineMode' in options && options['lineMode'] == 'staircase') {
+                lineMode = true;
+            }
+
             for (var res_i = 0; res_i < resp_graphite.length; res_i++) {
                 var target = find_definition(resp_graphite[res_i], options);
                 target.label = target.name // flot wants 'label'
@@ -184,11 +190,11 @@ function find_definition (target_graphite, options) {
             // default config state modifiers (you can override them in your config objects)
             var states = {
                 'stacked': {
-                    'series': {'stack': true, 'lines': {'show': true, 'lineWidth': 0, 'fill': 1}},
+                    'series': {'stack': true, 'lines': {'show': true, 'lineWidth': 0, 'fill': 1, 'steps': lineMode}},
                 },
                 'lines': {
                     // flot lib wants 0 or null. not false o_O
-                    'series': {'stack': null, 'lines': { 'show': true, 'lineWidth': 0.6, 'fill': false }}
+                    'series': {'stack': null, 'lines': { 'show': true, 'lineWidth': 0.6, 'fill': false, 'steps': lineMode }}
                 }
             };