allow 1D header in table

Author: monfera

src/traces/table/defaults.js

@@ -52,6 +52,12 @@ module.exports = function supplyDefaults(traceIn, traceOut, defaultColor, layout
     Lib.coerceFont(coerce, 'cells.font', fontDflt);
 
     coerce('header.values');
+    for(var i = 0; i < traceOut.header.values.length; i++) {
+        if(!Array.isArray(traceOut.header.values[i])) {
+            traceOut.header.values[i] = [traceOut.header.values[i]];
+        }
+    }
+
     coerce('header.format');
     coerce('header.align');
 

test/image/mocks/table_latex_multitrace.json

@@ -19,7 +19,7 @@
             "columnorder": [0, 1, 2],
 
             "header": {
-                "values": [["<b>#</b>"], ["Half-angle form"], ["Equivalent"]],
+                "values": ["<b>#</b>", "Half-angle form", "Equivalent"],
                 "align": ["right", "center", "center"],
                 "line": {"width": 0.0},
                 "fill": {"color": ["dimgray", "grey"]},