Update handlebars for htmlbars compat

WIP, needs some help/review and discussion :)

summary:
- [x] update AST names https://github.com/wycats/handlebars.js/commit/6a7a8c803d48b8a5768d00e8d1c73cf5012106d2
- [x] `foo.id._emblemSuffifModifier` gone, now needs `foo.path[0]._emblemSuffixModifier`
- [x] idNode and datanode replaced with pathExpression https://github.com/wycats/handlebars.js/commit/5c921cafebee438fa27d417ae701b24323373a30
- [ ] check if replacing ast names didnt have any sideeffect (was search and replace)

I'm currently working on: handlebars complains in function simpleId 
  * from debugging: a `SubExpression` should have `AST.PathExpression` as path parameter, but path is an array that contains an `AST.PathExpression`. Possibly just small change in `parseSexpr`.
This could change `foo.path[0]._emblemSuffixModifier` to `foo.path._emblemSuffixModifier`