Rewrite templates as objects

What's in your hand? Back at me. The templates are now objects.

- options.render is now options.template.
- templates must be called via `template.render(...)` instead of `template(...)`.

Example:

```hbs
{{#each items as |item|}}
  {{item.id}}: {{item.name}}
{{/each}}
```

now compiles to

```js
(function() {
  var child0 = (function() {
    return {
      isHTMLBars: true,
      cachedFragment: null,
      build: function build(dom) {
        var el0 = dom.createDocumentFragment();
        var el1 = dom.createTextNode("  ");
        dom.appendChild(el0, el1);
        var el1 = dom.createTextNode(": ");
        dom.appendChild(el0, el1);
        var el1 = dom.createTextNode("\n");
        dom.appendChild(el0, el1);
        return el0;
      },
      render: function render(context, env, contextualElement, blockArguments) {
        var dom = env.dom;
        var hooks = env.hooks, set = hooks.set, content = hooks.content;
        dom.detectNamespace(contextualElement);
        if (this.cachedFragment === null) {
          this.cachedFragment = this.build(dom);
        }
        var fragment = dom.cloneNode(this.cachedFragment, true);
        var morph0 = dom.createMorphAt(fragment,0,1,contextualElement);
        var morph1 = dom.createMorphAt(fragment,1,2,contextualElement);
        set(context, "item", blockArguments[0]);
        content(morph0, "item.id", context, [], {}, {morph:morph0}, env);
        content(morph1, "item.name", context, [], {}, {morph:morph1}, env);
        return fragment;
      }
    };
  }());
  return {
    isHTMLBars: true,
    cachedFragment: null,
    build: function build(dom) {
      var el0 = dom.createDocumentFragment();
      var el1 = dom.createTextNode("");
      dom.appendChild(el0, el1);
      var el1 = dom.createTextNode("");
      dom.appendChild(el0, el1);
      return el0;
    },
    render: function render(context, env, contextualElement) {
      var dom = env.dom;
      var hooks = env.hooks, get = hooks.get, content = hooks.content;
      dom.detectNamespace(contextualElement);
      if (this.cachedFragment === null) {
        this.cachedFragment = this.build(dom);
      }
      var fragment = dom.cloneNode(this.cachedFragment, true);
      dom.repairClonedNode(fragment,[0,1]);
      var morph0 = dom.createMorphAt(fragment,0,1,contextualElement);
      content(morph0, "each", context, [get(context, "items", env)], {}, {template:child0,morph:morph0,blockParams:1}, env);
      return fragment;
    }
  };
}())
```