APPS reusable template example app

:koala: :+1:

A new app that shows how to use `this.renderTemplate()` to recycle common elements.

/cc @zendesk/quokka

### References
 - Jira link: 

### Risks
 - None

### Screenshot
![screen shot 2014-09-12 at 1 44 39 pm](https://cloud.githubusercontent.com/assets/5535625/4245137/522167c6-3a2f-11e4-9d44-5145511e78ab.png)
Go for it if my comments are addressed

On phone now

On Thursday, September 11, 2014, Adam Malcontenti-Wilson <
notifications@github.com> wrote:

> In reuseable_template_app/app.js:
>
> > @@ -0,0 +1,27 @@
> > +(function() {
> > +
> > +  return {
> > +    events: {
> > +      'app.activated': 'greet',
> > +      'click a': 'handleButton'
> > +    },
> > +
> > +    greet: function(type) {
> > +      if (typeof type != 'string') {
> > +        type = 'hello';
> > +      }
> > +      var currentUser = this.currentUser().name();
> > +      var boilerPlate = this.renderTemplate('boilerplate', {username: currentUser});
>
> #nitpick can we do { username: currentUser }?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/zendesk/demo_apps/pull/62/files#r17462195>.
>


-- 
Maxime Prades
Platform Product Manager

Zendesk <http://www.zendesk.com/>
 (415) 623 8234 | @prades_maxime