Revert "Revert "{{input}} helper with bindings are now recognized in child helpers""

This reverts commit f5f2be5984eff3a22c67c9600fffcd76384d002a.
Changing {{{errorField}} to {{errorField}} (typo).

I was getting a parse error in Handlebars 1.0: Expecting 'CLOSE_UNESCAPED', got 'CLOSE'
Merge pull request #33 from karlguillotte/master

{{input}} helper with bindings are now recognized in child helpers