Add ol.easing.linear

src/ol/easing.js

@@ -1,6 +1,15 @@
 goog.provide('ol.easing');
 
 
+/**
+ * @param {number} t Input between 0 and 1.
+ * @return {number} Output between 0 and 1.
+ */
+ol.easing.linear = function(t) {
+  return t;
+};
+
+
 /**
  * @param {number} t Input between 0 and 1.
  * @return {number} Output between 0 and 1.