add experiment.js to the sdk

plugins/c9.ide.experiment/mock_experiment.js

@@ -0,0 +1,26 @@
+/**
+ * Dummy implementation of experiments.
+ */
+"use strict";
+
+plugin.consumes = [];
+plugin.provides = ["experiment"];
+
+module.exports = plugin;
+
+function plugin(options, imports, register) {
+    
+     register(null, {
+        "experiment": {
+            configureExperiment: function() {},
+            onStart: function() {
+                var chain = {
+                    variation: function() {
+                        return chain;
+                    }
+                }
+                return chain;
+            }
+        }
+    });
+}