[Feature] Allow to render flow layout inside templates

[arunoda]

So, we'll have FlowLayout.render() or similar API for use with just within templates.
So, we can have nested layouts in style.

<template name='kadira-debug'>
  <h1> This is My Sub Component.
  <!-- Here's getData is a template helper which gives us data -->
  {{>FlowLayout render="kadira-debug-layout" data=getData}}
</template>

[arunoda]

This is dynamic templates :)