Enhance renderEmber, use new ember main

1. enhanced renderEmber function so that .htm* files will be rendered
directly instead of adding script tag.
2. Update ember.js with newest from main branch.  Update controller js
with new router syntax and new insertNewline action
3. Fix template bug that return is always triggered to <button
{{action}}>>, go back to using view for now
4. Fix template bug that delete todo action doesn't work, making its
target to "view" instead, this is something changed in ember.js since
pre-1