Improve dmx-repeat

Improve dmx-repeat

There's a design issue in dmx-repeat that makes it undesirable for nested looping. Other frameworks do like this:

<li v-for="item in items">
  {{ item.message }}
</li>

The item being iterated is in the item variable, but in dmx-repeat there's no such thing - the variables are directly bound to the current scope, making collisions highly likely when performing nested loops.