fix(examples): Modifies web worker examples to be compatible with systemjs 0.18.10.

Adds the rx path to each respective web worker loader.

Closes #3630

modules/examples/src/message_broker/loader.js

@@ -18,7 +18,13 @@ window = {
 assert = function(){};
 
 
-System.config({baseURL: '/', defaultJSExtensions: true});
+System.config({
+  baseURL: '/',
+  defaultJSExtensions: true,
+  paths: {
+    'rx': 'examples/src/message_broker/rx.js'
+  }
+});
 
 System.import("examples/src/message_broker/background_index").then(function(m){
   console.log("running main");

modules/examples/src/web_workers/images/loader.js

@@ -15,7 +15,13 @@ assert = function() {};
 importScripts("b64.js");
 
 
-System.config({baseURL: '/', defaultJSExtensions: true});
+System.config({
+  baseURL: '/',
+  defaultJSExtensions: true,
+  paths: {
+    'rx': 'examples/src/web_workers/images/rx.js'
+  }
+});
 
 System.import("examples/src/web_workers/images/background_index")
     .then(

modules/examples/src/web_workers/kitchen_sink/loader.js

@@ -14,7 +14,13 @@ window = {
 assert = function() {};
 
 
-System.config({baseURL: '/', defaultJSExtensions: true});
+System.config({
+  baseURL: '/',
+  defaultJSExtensions: true,
+  paths: {
+    'rx': 'examples/src/web_workers/kitchen_sink/rx.js'
+  }
+});
 
 System.import("examples/src/web_workers/kitchen_sink/background_index")
     .then(

modules/examples/src/web_workers/todo/loader.js

@@ -14,7 +14,13 @@ window = {
 assert = function() {};
 
 
-System.config({baseURL: '/', defaultJSExtensions: true});
+System.config({
+  baseURL: '/',
+  defaultJSExtensions: true,
+  paths: {
+    'rx': 'examples/src/web_workers/todo/rx.js'
+  }
+});
 
 System.import("examples/src/web_workers/todo/background_index")
     .then(