contour line-colored label test

Author: alexcjohnson

test/image/baselines/contour_lines_coloring.png

@@ -1,6 +1,6 @@
 {
   "data":[{
-    "contours":{"coloring":"lines"},
+    "contours":{"coloring":"lines", "showlabels": true},
     "z":[["1",""],["2",""],["3",""],["3",""],["4",""],["5",""],["6",""],["5",""],["2",""],["3",""],["3",""],["5",""],["6",""],["5",""],["4","1"],["4","2"],["2","3"],["1","4"],["3","5"],["2","4"],["1","3"],["3","2"],["5","3"],["4","4"],["3","3"],["2","2"],["1","1"],["2","2"],["3","3"],["4","4"],["5","6"],["4","5"],["3","4"],["2","3"],["3","2"],["2","3"],["3","4"],["3","3"],["3","2"]],
     "type":"contour"
   }],