[BUGFIX beta] Bump HTMLBars to 0.7.0
[BUGFIX beta] Use attrMorph, properties before attributes

HTMLBars is responsible for managing escaped and sanitizaition of bound
attributes. It uses an AttrMorph construct to do this. Consequently the
bind-attr and htmlbars attr syntaxes are much simpler to implement.
Merge pull request #10066 from mixonic/render-marph

[BUGFIX beta] WIP AttrNodes managed by renderer, update to new HTMLBars hooks