oncreate order should reflect component order

[Rich-Harris]

No REPL, pending sveltejs/v2.svelte.dev#205, but if you have a situation like this...

<!-- App.html -->
<Nested name='foo'/>
<Nested name='bar'/>

<script>
  import Nested from './Nested.html';

  export default {
    components: {
      Nested
    }
  };
</script>

<!-- Nested.html -->
<p>{{name}}</p>

<script>
  export default {
    oncreate() {
      console.log(`oncreate ${this.get('name')}`);
    }
  };
</script>

...you would reasonably expect the console to show

oncreate foo
oncreate bar

but the order is reversed. This breaks expectations and makes it harder to, for example, wait for some data for foo to load before attempting to load data for bar (which is exactly what I'm currently experiencing).

I think this qualifies as a bug, so reversing the order needn't be considered a breaking change.

[Conduitry]

I imagine this should be an .unshift - or else this should be a .shift. Not sure how or whether we should be worrying about _beforecreate or _aftercreate.