test new histogram logic in images

Author: alexcjohnson

test/image/baselines/hist_grouped.png

@@ -1,10 +1,10 @@
 {
     "data":[{
-        "x":["1","2","3","4"],
-        "type":"histogram"
-    },{
-        "x":["1","2","3","4"],
-        "type":"histogram"
+        "x": [1, 1, 1, 2, 2],
+        "type": "histogram"
+    }, {
+        "x": [1, 2, 3, 4],
+        "type": "histogram"
     }],
-    "layout":{"height":300,"width":400}
+    "layout": {"height": 300, "width": 400}
 }

test/image/baselines/hist_stacked.png

@@ -1,10 +1,10 @@
 {
-    "data":[{
-        "x":["1","2","3","4"],
-        "type":"histogram"
-    },{
-        "x":["1","2","3","4"],
-        "type":"histogram"
+    "data": [{
+        "x": [1, 1, 1, 2, 2],
+        "type": "histogram"
+    }, {
+        "x": [1, 2, 3, 4],
+        "type": "histogram"
     }],
-    "layout":{"height":300,"width":400,"barmode":"stack"}
+    "layout": {"height": 300, "width": 400, "barmode": "stack"}
 }