short-circuit spike properties when spikes are off

Author: alexcjohnson

src/plots/cartesian/layout_defaults.js

@@ -173,11 +173,13 @@ module.exports = function supplyLayoutDefaults(layoutIn, layoutOut, fullData) {
 
         handleAxisDefaults(axLayoutIn, axLayoutOut, coerce, defaultOptions, layoutOut);
 
-        coerce('showspikes');
-        coerce('spikecolor');
-        coerce('spikethickness');
-        coerce('spikedash');
-        coerce('spikemode');
+        var showSpikes = coerce('showspikes');
+        if(showSpikes) {
+            coerce('spikecolor');
+            coerce('spikethickness');
+            coerce('spikedash');
+            coerce('spikemode');
+        }
 
         var positioningOptions = {
             letter: axLetter,