Specs: Update parser to support <t>, <template>, "/>" syntax
Specs: Fix scripts to run at </script> not <script>
Specs: Update parsing to delay on pending imports before running
scripts or firing 'load'
Specs: Fire 'load' at Application or Module rather than Document
Specs: Imply there's going to be a start tag token observer callback
so that you can implement prefetching for custom elements

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/677533004