allow autotickangles for polar radial axes

Author: alexcjohnson

src/plots/polar/layout_attributes.js

@@ -105,6 +105,8 @@ var radialAxisAttrs = {
         ].join(' ')
     },
 
+    autotickangles: axesAttrs.autotickangles,
+
     side: {
         valType: 'enumerated',
         // TODO add 'center' for `showline: false` radial axes

src/plots/polar/layout_defaults.js

@@ -168,7 +168,7 @@ function handleDefaults(contIn, contOut, coerce, opts) {
                     size: dfltFontSize,
                     family: dfltFontFamily
                 },
-                noAutotickangles: true
+                noAutotickangles: axName === 'angularaxis'
             });
 
             handleTickMarkDefaults(axIn, axOut, coerceAxis, {outerTicks: true});