Fix compiler-api example (#1303)

Closes #1302 

While trying to answer #1302, I noticed that the compiler-api example did not work in (because `nameLookup` is actually at the prototype). This example has a jsfiddle that proves it is working.
It does not provide an solve the exact problem of the reporter, but it answers the question.

docs/compiler-api.md

@@ -296,21 +296,36 @@ The `Handlebars.JavaScriptCompiler` object has a number of methods that may be c
 - `initializeBuffer()`
     Allows for buffers other than the default string buffer to be used. Generally needs to be paired with a custom `appendToBuffer` implementation.
 
+### Example for the compiler api.
+
+This example changes all lookups of properties are performed by a helper (`lookupLowerCase`) which looks for `test` if `{{Test}}` occurs in the template. This is just to illustrate how compiler behavior can be change.
+
+There is also [a jsfiddle with this code](https://jsfiddle.net/9D88g/85/) if you want to play around with it.
+
+
 ```javascript
 function MyCompiler() {
   Handlebars.JavaScriptCompiler.apply(this, arguments);
 }
-MyCompiler.prototype = Object.create(Handlebars.JavaScriptCompiler);
+MyCompiler.prototype = new Handlebars.JavaScriptCompiler();
 
-MyCompiler.nameLookup = function(parent, name, type) {
-  if (type === 'partial') {
-    return 'MyPartialList[' + JSON.stringify(name) ']';
+MyCompiler.prototype.nameLookup = function(parent, name, type) {
+  if (type === 'context') {
+    return this.source.functionCall('helpers.lookupLowerCase', '', [parent, JSON.stringify(name)])
   } else {
     return Handlebars.JavaScriptCompiler.prototype.nameLookup.call(this, parent, name, type);
   }
-};
+}
 
 var env = Handlebars.create();
+env.registerHelper('lookupLowerCase', function(parent, name) {
+  return parent[name.toLowerCase()]
+})
+
 env.JavaScriptCompiler = MyCompiler;
-env.compile('my template');
+
+var template = env.compile('{{#each Test}}{{.}} {{/each}}');
+console.log(template({
+  test: [ "a","b","c"]
+}));
 ```