write own heatmapgl attributes

- instead of simply copying attribute from 'heatmap'
- attribute like 'zsmooth', 'xgap' and 'connectgaps'
  aren't available in 'heatmapgl'

Author: etpinard

src/traces/heatmapgl/attributes.js

@@ -10,5 +10,31 @@
 
 
 var heatmapAttrs = require('../scatter/attributes');
+var colorscaleAttrs = require('../../components/colorscale/attributes');
+var colorbarAttrs = require('../../components/colorbar/attributes');
 
-module.exports = heatmapAttrs;
+var extendFlat = require('../../lib/extend').extendFlat;
+
+var commonList = [
+    'z',
+    'x', 'x0', 'dx',
+    'y', 'y0', 'dy',
+    'text', 'transpose',
+    'xtype', 'ytype'
+];
+
+var attrs = {};
+
+for(var i = 0; i < commonList.length; i++) {
+    var k = commonList[i];
+    attrs[k] = heatmapAttrs[k];
+}
+
+extendFlat(
+    attrs,
+    colorscaleAttrs,
+    { autocolorscale: extendFlat({}, colorscaleAttrs.autocolorscale, {dflt: false}) },
+    { colorbar: colorbarAttrs }
+);
+
+module.exports = attrs;