Merging in Pull Request #43 fixiing Issue #42 MultibarChart set to stacked, the controls default value is wrong

nv.d3.js

@@ -4076,8 +4076,8 @@ nv.models.multiBarChart = function() {
 
   //TODO: let user select default
   var controlsData = [
-    { key: 'Grouped' },
-    { key: 'Stacked', disabled: true }
+    { key: 'Grouped', disabled: multibar.stacked },
+    { key: 'Stacked', disabled: !multibar.stacked }
   ];
 
   function chart(selection) {

src/models/multiBarChart.js

@@ -36,8 +36,8 @@ nv.models.multiBarChart = function() {
 
   //TODO: let user select default
   var controlsData = [
-    { key: 'Grouped' },
-    { key: 'Stacked', disabled: true }
+    { key: 'Grouped', disabled: multibar.stacked },
+    { key: 'Stacked', disabled: !multibar.stacked }
   ];
 
   function chart(selection) {