Added sample for custom hit renderer

examples/custom-hit-detection-renderer.html

@@ -0,0 +1,12 @@
+---
+layout: example.html
+title: Custom Hit Detection Render
+shortdesc: Example of a custom hit detection renderer.
+docs: >
+  This example demonstrates the use of 'ol/style/Style' hitDetectionRender option function in 
+  detecting if pointer is over a particular feature. 
+  Move pointer over the label for Columbus Circle feature and see that only label is used in
+  hit detection.
+tags: "circle, feature, vector, render, custom, hitDetectionRenderer"
+---
+<div id="map" class="map"></div>