Removed the need for template_id in {% handlebars %} templatetag.

[akarl]

Removed the need for template_id so you can do this inside a django-template:

{% load ember %}
{% handlebars %}
    {{#view App.MyView}}
        <p>{{view.someVariable}}</p>
        <p>No data-template-name in here.</p>
    {{/view}}
{% endhandlebars %}

and:

{% handlebars %}
    {{view App.MySpecialButton}}
{% endhandlebars %}

[travisbot]

This pull request passes (merged de1e4e5 into aa29481).