test: bar texts

* bar_test.js: Test `textposition`.

* bar_test.js: Test that `textposition` can also be restyled.

* bar_test.js: Test whether outside bars are correctly identified when
  `barnorm: 'fraction'`.

* bar_attrs_relative: Updated to test the bar text functionality.

* bar_attrs_group_norm: Updated to test the bar text functionality.

* bar_attrs_relative: Reduced font size of text "Three" to ensure the
  baseline image also fits the text inside the bar.

* bar_attrs_group_norm: Exercise functionality to rotate bar texts.

* bar_attrs_group_norm: Use "50%" as bar texts to ensure the bounding
  box width is larger than its height (unfortunately, this wasn't case
  when the baseline images were generated using "0.5", because the
  height of the bounding box includes some white space).

Author: n-riesco

test/image/baselines/bar_attrs_group_norm.png

@@ -1,10 +1,15 @@
 {
     "data":[
         {
+            "text":"50%",
+            "textposition":"inside",
+            "outsidetextfont": {"size":32},
             "base":[100,40,25,10],
             "x":[-50,10,25,40],
             "type":"bar"
         }, {
+            "text":"50%",
+            "textposition":"outside",
             "base":[0,60,75,90],
             "x":[50,-10,-25,-40],
             "type":"bar"

test/image/baselines/bar_attrs_relative.png

@@ -2,27 +2,37 @@
     "data":[
         {
             "width":[1,0.8,0.6,0.4],
+            "text":[1,2,3333333333,4],
+            "textposition":"outside",
             "y":[1,2,3,4],
             "x":[1,2,3,4],
             "type":"bar"
         }, {
             "width":[0.4,0.6,0.8,1],
+            "text":["Three",2,"inside text",0],
+            "textposition":"auto",
+            "textfont":{"size":[10]},
             "y":[3,2,1,0],
             "x":[1,2,3,4],
             "type":"bar"
         }, {
             "width":1,
+            "text":[-1,-3,-2,-4],
+            "textposition":"inside",
             "y":[-1,-3,-2,-4],
             "x":[1,2,3,4],
             "type":"bar"
         }, {
-            "y":[0,-1,-3,-2],
+            "text":[0,"outside text",-3,-2],
+            "textposition":"auto",
+            "y":[0,-0.25,-3,-2],
             "x":[1,2,3,4],
             "type":"bar"
         }
     ],
     "layout":{
         "xaxis": {"showgrid":true},
+        "yaxis": {"range":[-6,6]},
         "height":400,
         "width":400,
         "barmode":"relative",