unclear stuff iterator should call helperResolver

[dreyks]

issue: I have all my helpers in one directory but I also have {{variable}} references where variable coincides with a template name in the same directory. So the unclear stuff resolver tries to resolve the file and finds it cause it's there, and it thinks that it's a helper, but it's not. All i need is a variable

So it would be nice if instead of just calling resolve the iterator would call helperResolver provided in webpack config. After all the unclear stuff could only be a helper

https://github.com/pcardune/handlebars-loader/blob/a8a9773824710d8e774a7388a10602bd10430bad/index.js#L272

UPD: opened #157