Update to latest HTMLBars.

* Add compiler options to allow disabling component generation.
* Implement quoted and unquoted attribute semantics.
* Rewrite attribute helper as a hook.
* Add `DomHelper.prototype.removeAttribute`.

Compare view:
https://github.com/tildeio/htmlbars/compare/v0.1.5...v0.1.7
Merge pull request #9672 from rwjblue/htmlbars-update-attribute-hook

Update to latest HTMLBars.