lack of partials support for handlebars

The way the --hbs options currently works doesnt support partials, i suspect that it might be possible to change that without the use of an additional package, but there was a package designed specifically with this in mind, so i figured id use that instead.

In #161 I jumped the gun on the discussion phase and already submitted a replacement of the handlebars package which DG also maintains, and coded up the rest of the suggestions he laid out there. My plan is to resubmit a PR next week taking into account any feedback i get here, and also see if i can figure out how to get DG's handlebars package to support partials the way the package i found does.